Fluid: restructuring and rejuvenation of the source code.

* Add classes for application and project
* Removed all globals from Fluid.h
* Extracting args and project history into their own classes
* Moving globals into Application class
* Initialize values inside headers for some classes.
* Undo functionality wrapped in a class inside Project.
* File reader and writer are now linked to a project.
* Avoid global project access
* Nodes (former Types) will be managed by a new Tree class.
* Removed static members (hidden globals) form Node/Fl_Type.
* Adding Tree iterator.
* Use nullptr instead of 0, NULL, or 0L
* Renamed Fl_..._Type to ..._Node, FL_OVERRIDE -> override
* Renaming ..._type to ...::prototype
* Splitting Widget Panel into multiple files.
* Moved callback code into widget panel file.
* Cleaning up Fluid_Image -> Image_asset
* Moving Fd_Snap_Action into new namespace fld::app::Snap_Action etc.
* Moved mergeback into proj folder.
* `enum ID` is now `enum class Type`.

11 files changed, 87 insertions, 85 deletions

diff --git a/fluid/widgets/Bin_Button.cxx b/fluid/widgets/Bin_Button.cxx
index 308d12234..32630369a 100644
--- a/fluid/widgets/Bin_Button.cxx
+++ b/fluid/widgets/Bin_Button.cxx
@@ -16,9 +16,9 @@
 
 #include "widgets/Bin_Button.h"
 
-#include "app/fluid.h"
+#include "Fluid.h"
 #include "nodes/factory.h"
-#include "nodes/Fl_Window_Type.h"
+#include "nodes/Window_Node.h"
 #include "widgets/Node_Browser.h"
 
 #include <FL/Fl_Button.H>
@@ -57,7 +57,7 @@ int fld::widget::Bin_Button::handle(int inEvent)
         Fl_Button::handle(FL_RELEASE);
         // make it into a dnd event
         const char *type_name = (const char*)user_data();
-        Fl_Type::current_dnd = Fl_Type::current;
+        Fluid.proj.tree.current_dnd = Fluid.proj.tree.current;
         Fl::copy(type_name, (int)strlen(type_name)+1, 0);
         Fl::dnd();
         return 1;
@@ -81,7 +81,7 @@ int fld::widget::Bin_Button::handle(int inEvent)
  */
 int fld::widget::Bin_Window_Button::handle(int inEvent)
 {
-  static Fl_Window *drag_win = NULL;
+  static Fl_Window *drag_win = nullptr;
   int ret = 0;
   switch (inEvent) {
     case FL_PUSH:
@@ -107,18 +107,18 @@ int fld::widget::Bin_Window_Button::handle(int inEvent)
     case FL_RELEASE:
       if (drag_win) {
         Fl::delete_widget(drag_win);
-        drag_win = NULL;
+        drag_win = nullptr;
         // create a new window here
-        Fl_Type *prototype = typename_to_prototype((char*)user_data());
+        Node *prototype = typename_to_prototype((char*)user_data());
         if (prototype) {
-          Fl_Type *new_type = add_new_widget_from_user(prototype, Strategy::AFTER_CURRENT);
-          if (new_type && new_type->is_a(ID_Window)) {
-            Fl_Window_Type *new_window = (Fl_Window_Type*)new_type;
+          Node *new_type = add_new_widget_from_user(prototype, Strategy::AFTER_CURRENT);
+          if (new_type && new_type->is_a(Type::Window)) {
+            Window_Node *new_window = (Window_Node*)new_type;
             Fl_Window *w = (Fl_Window *)new_window->o;
             w->position(Fl::event_x_root(), Fl::event_y_root());
           }
         }
-        widget_browser->display(Fl_Type::current);
+        widget_browser->display(Fluid.proj.tree.current);
         widget_browser->rebuild();
       }
       return Fl_Button::handle(inEvent);
diff --git a/fluid/widgets/Code_Editor.cxx b/fluid/widgets/Code_Editor.cxx
index a145b5055..b4379c845 100644
--- a/fluid/widgets/Code_Editor.cxx
+++ b/fluid/widgets/Code_Editor.cxx
@@ -1,6 +1,5 @@
 //
 // Code editor widget for the Fast Light Tool Kit (FLTK).
-// Syntax highlighting rewritten by erco@seriss.com 09/15/20.
 //
 // Copyright 1998-2025 by Bill Spitzak and others.
 //
@@ -15,6 +14,8 @@
 //     https://www.fltk.org/bugs.php
 //
 
+// Syntax highlighting rewritten by erco@seriss.com 09/15/20.
+
 //
 // Include necessary headers...
 //
@@ -230,11 +231,11 @@ Code_Editor::Code_Editor(int X, int Y, int W, int H, const char *L) :
  */
 Code_Editor::~Code_Editor() {
   Fl_Text_Buffer *buf = mStyleBuffer;
-  mStyleBuffer = 0;
+  mStyleBuffer = nullptr;
   delete buf;
 
   buf = mBuffer;
-  buffer(0);
+  buffer(nullptr);
   delete buf;
 }
 
diff --git a/fluid/widgets/Code_Editor.h b/fluid/widgets/Code_Editor.h
index ef8df0e0d..49afe7e25 100644
--- a/fluid/widgets/Code_Editor.h
+++ b/fluid/widgets/Code_Editor.h
@@ -1,6 +1,5 @@
 //
 // Code editor widget for the Fast Light Tool Kit (FLTK).
-// Syntax highlighting rewritten by erco@seriss.com 09/15/20.
 //
 // Copyright 1998-2025 by Bill Spitzak and others.
 //
@@ -18,6 +17,8 @@
 #ifndef FLUID_WIDGETS_CODE_EDITOR_H
 #define FLUID_WIDGETS_CODE_EDITOR_H
 
+// Syntax highlighting rewritten by erco@seriss.com 09/15/20.
+
 //
 // Include necessary headers...
 //
@@ -49,7 +50,7 @@ class Code_Editor : public Fl_Text_Editor {
   static int auto_indent(int, Code_Editor* e);
 
 public:
-  Code_Editor(int X, int Y, int W, int H, const char *L=0);
+  Code_Editor(int X, int Y, int W, int H, const char *L=nullptr);
   ~Code_Editor();
   void textsize(Fl_Fontsize s);
 
diff --git a/fluid/widgets/Code_Viewer.cxx b/fluid/widgets/Code_Viewer.cxx
index 82a71f4f6..fdbfdc626 100644
--- a/fluid/widgets/Code_Viewer.cxx
+++ b/fluid/widgets/Code_Viewer.cxx
@@ -1,6 +1,5 @@
 //
-// Code editor widget for the Fast Light Tool Kit (FLTK).
-// Syntax highlighting rewritten by erco@seriss.com 09/15/20.
+// Code viewer widget for the Fast Light Tool Kit (FLTK).
 //
 // Copyright 1998-2025 by Bill Spitzak and others.
 //
@@ -15,6 +14,8 @@
 //     https://www.fltk.org/bugs.php
 //
 
+// Syntax highlighting rewritten by erco@seriss.com 09/15/20.
+
 //
 // Include necessary headers...
 //
diff --git a/fluid/widgets/Code_Viewer.h b/fluid/widgets/Code_Viewer.h
index 5bf8b870a..4198fd433 100644
--- a/fluid/widgets/Code_Viewer.h
+++ b/fluid/widgets/Code_Viewer.h
@@ -1,6 +1,5 @@
 //
-// Code editor widget for the Fast Light Tool Kit (FLTK).
-// Syntax highlighting rewritten by erco@seriss.com 09/15/20.
+// Code viewer widget for the Fast Light Tool Kit (FLTK).
 //
 // Copyright 1998-2025 by Bill Spitzak and others.
 //
@@ -18,6 +17,8 @@
 #ifndef FLUID_WIDGETS_CODE_VIEWER_H
 #define FLUID_WIDGETS_CODE_VIEWER_H
 
+// Syntax highlighting rewritten by erco@seriss.com 09/15/20.
+
 //
 // Include necessary headers...
 //
diff --git a/fluid/widgets/Formula_Input.cxx b/fluid/widgets/Formula_Input.cxx
index b26bd83e3..dadebe674 100644
--- a/fluid/widgets/Formula_Input.cxx
+++ b/fluid/widgets/Formula_Input.cxx
@@ -1,5 +1,5 @@
 //
-// Widget type code for the Fast Light Tool Kit (FLTK).
+// Formula Int Input widget code for the Fast Light Tool Kit (FLTK).
 //
 // Copyright 1998-2025 by Bill Spitzak and others.
 //
@@ -209,7 +209,7 @@ int Formula_Input::handle(int event) {
 }
 
 /** Set the list of the available variables
- \param vars array of variables, last entry `has name_` set to `NULL`
+ \param vars array of variables, last entry `has name_` set to `nullptr`
  \param user_data is forwarded to the Variable callback */
 void Formula_Input::variables(Formula_Input_Vars *vars, void *user_data) {
   vars_ = vars;
diff --git a/fluid/widgets/Formula_Input.h b/fluid/widgets/Formula_Input.h
index 5307cdc88..060c1e157 100644
--- a/fluid/widgets/Formula_Input.h
+++ b/fluid/widgets/Formula_Input.h
@@ -1,5 +1,5 @@
 //
-// Formula_Input widget header file for the Fast Light Tool Kit (FLTK).
+// Formula Int Input widget header file for the Fast Light Tool Kit (FLTK).
 //
 // Copyright 1998-2025 by Bill Spitzak and others.
 //
@@ -29,7 +29,7 @@ typedef int (Fluid_Coord_Callback)(Formula_Input const *, void*);
 
 // Entry for a list of variables available to an input field.
 // Formula_Input::variables() expects an array of
-// Formula_Input_Vars with the last entry's name_ set to NULL.
+// Formula_Input_Vars with the last entry's name_ set to nullptr.
 typedef struct Formula_Input_Vars {
   const char *name_;
   Fluid_Coord_Callback *callback_;
diff --git a/fluid/widgets/Node_Browser.cxx b/fluid/widgets/Node_Browser.cxx
index fafe236cf..745282e23 100644
--- a/fluid/widgets/Node_Browser.cxx
+++ b/fluid/widgets/Node_Browser.cxx
@@ -1,5 +1,5 @@
 //
-// Widget Browser code for the Fast Light Tool Kit (FLTK).
+// Widget Tree Browser code for the Fast Light Tool Kit (FLTK).
 //
 // Copyright 1998-2025 by Bill Spitzak and others.
 //
@@ -16,8 +16,8 @@
 
 #include "widgets/Node_Browser.h"
 
-#include "app/fluid.h"
-#include "nodes/Fl_Widget_Type.h"
+#include "Fluid.h"
+#include "nodes/Widget_Node.h"
 #include "rsrcs/pixmaps.h"
 
 #include <FL/Fl.H>
@@ -41,9 +41,9 @@ using namespace fld::widget;
 
  The Widget Browser is derived from the FLTK basic browser, extending
  tree browsing functionality by using the \c depth component of the double
- linked list of \c Fl_Type items.
+ linked list of \c Node items.
 
- \see Fl_Type
+ \see Node
  */
 
 
@@ -81,9 +81,9 @@ Fl_Widget *make_widget_browser(int x,int y,int w,int h) {
 /**
  Make sure that the caller is visible in the widget browser.
  \param[in] caller scroll the browser in y so that caller
- is visible (may be NULL)
+ is visible (may be nullptr)
  */
-void redraw_widget_browser(Fl_Type *caller)
+void redraw_widget_browser(Node *caller)
 {
   if (caller)
     widget_browser->display(caller);
@@ -95,7 +95,7 @@ void redraw_widget_browser(Fl_Type *caller)
  \param[in] o (de)select this node
  \param[in] v the new selection state (1=select, 0=de-select)
  */
-void select(Fl_Type *o, int v) {
+void select(Node *o, int v) {
   widget_browser->select(o,v,1);
 }
 
@@ -103,7 +103,7 @@ void select(Fl_Type *o, int v) {
  Select a single node in the widget browser, deselect all others.
  \param[in] o select this node
  */
-void select_only(Fl_Type *o) {
+void select_only(Node *o) {
   widget_browser->select_only(o,1);
 }
 
@@ -122,8 +122,8 @@ void deselect() {
 
  \param[in] t show this item
  */
-void reveal_in_browser(Fl_Type *t) {
-  Fl_Type *p = t->parent;
+void reveal_in_browser(Node *t) {
+  Node *p = t->parent;
   if (p) {
     for (;;) {
       if (p->folded_)
@@ -165,7 +165,7 @@ static char *copy_trunc(char *p, const char *str, int maxl, int quote, int trunc
 {
   int size = 0;                         // truncated string size in characters
   int bs;                               // size of UTF-8 character in bytes
-  if (!p) return NULL;                  // bad buffer
+  if (!p) return nullptr;                  // bad buffer
   if (!str) {                           // no input string
     if (quote) { *p++='"'; *p++='"'; }
     *p = 0;
@@ -206,7 +206,7 @@ static char *copy_trunc(char *p, const char *str, int maxl, int quote, int trunc
 
  Fluid currently generates only one instance of this browser. If we want
  to use multiple browser at some point, we need to refactor a few global
- variables, i.e. Fl_Type::first and Fl_Type::last .
+ variables, i.e. Fluid.proj.tree.first and Fluid.proj.tree.last .
 
  \param[in] X, Y, W, H position and size of widget
  \param[in] l optional label
@@ -226,25 +226,25 @@ Node_Browser::Node_Browser(int X,int Y,int W,int H,const char*l) :
  \return the first item
  */
 void *Node_Browser::item_first() const {
-  return Fl_Type::first;
+  return Fluid.proj.tree.first;
 }
 
 /**
  Override the method to find the next item in the list of elements.
  \param l this item
- \return the next item, irregardless of tree depth, or NULL at the end
+ \return the next item, irregardless of tree depth, or nullptr at the end
  */
 void *Node_Browser::item_next(void *l) const {
-  return ((Fl_Type*)l)->next;
+  return ((Node*)l)->next;
 }
 
 /**
  Override the method to find the previous item in the list of elements.
  \param l this item
- \return the previous item, irregardless of tree depth, or NULL at the start
+ \return the previous item, irregardless of tree depth, or nullptr at the start
  */
 void *Node_Browser::item_prev(void *l) const {
-  return ((Fl_Type*)l)->prev;
+  return ((Node*)l)->prev;
 }
 
 /**
@@ -254,7 +254,7 @@ void *Node_Browser::item_prev(void *l) const {
  \todo what is the difference between selected and new_selected, and why do we do this?
  */
 int Node_Browser::item_selected(void *l) const {
-  return ((Fl_Type*)l)->new_selected;
+  return ((Node*)l)->new_selected;
 }
 
 /**
@@ -263,7 +263,7 @@ int Node_Browser::item_selected(void *l) const {
  \param[in] v 1 if selecting, 0 if not
  */
 void Node_Browser::item_select(void *l,int v) {
-  ((Fl_Type*)l)->new_selected = v;
+  ((Node*)l)->new_selected = v;
 }
 
 /**
@@ -272,9 +272,9 @@ void Node_Browser::item_select(void *l,int v) {
  \return height in FLTK units (used to be pixels before high res screens)
  */
 int Node_Browser::item_height(void *l) const {
-  Fl_Type *t = (Fl_Type*)l;
+  Node *t = (Node*)l;
   if (t->visible) {
-    if (show_comments && t->comment())
+    if (Fluid.show_comments && t->comment())
       return textsize()*2+4;
     else
       return textsize()+5;
@@ -307,13 +307,13 @@ int Node_Browser::incr_height() const {
  text, possibly abbreviated with an ellipsis.
 
  \param v      v is a pointer to the actual widget type and can be cast safely
-    to Fl_Type
+    to Node
  \param X,Y    these give the position in window coordinates of the top left
     corner of this line
  */
 void Node_Browser::item_draw(void *v, int X, int Y, int, int) const {
   // cast to a more general type
-  Fl_Type *l = (Fl_Type *)v;
+  Node *l = (Node *)v;
 
   char buf[500]; // edit buffer: large enough to hold 80 UTF-8 chars + nul
 
@@ -331,7 +331,7 @@ void Node_Browser::item_draw(void *v, int X, int Y, int, int) const {
   // items can contain a comment. If they do, the comment gets a second text
   // line inside this browser line
   int comment_incr = 0;
-  if (show_comments && l->comment()) {
+  if (Fluid.show_comments && l->comment()) {
     // -- comment
     copy_trunc(buf, l->comment(), 80, 0, 1);
     comment_incr = textsize()-1;
@@ -370,7 +370,7 @@ void Node_Browser::item_draw(void *v, int X, int Y, int, int) const {
   }
 
   // Width=18: Draw the icon associated with the type.
-  Fl_Pixmap *pm = pixmap[l->id()];
+  Fl_Pixmap *pm = pixmap[(int)l->type()];
   if (pm) pm->draw(X-18, Y);
 
   // Add tags on top of the icon for locked and protected types.
@@ -380,11 +380,11 @@ void Node_Browser::item_draw(void *v, int X, int Y, int, int) const {
   }
 
   if (   l->is_widget()
-      && !l->is_a(ID_Window)
-      && ((Fl_Widget_Type*)l)->o
-      && !((Fl_Widget_Type*)l)->o->visible()
-      && (!l->parent || (   !l->parent->is_a(ID_Tabs)
-                         && !l->parent->is_a(ID_Wizard) ) )
+      && !l->is_a(Type::Window)
+      && ((Widget_Node*)l)->o
+      && !((Widget_Node*)l)->o->visible()
+      && (!l->parent || (   !l->parent->is_a(Type::Tabs)
+                         && !l->parent->is_a(Type::Wizard) ) )
       )
   {
     invisible_pixmap->draw(X - 17, Y);
@@ -424,7 +424,7 @@ void Node_Browser::item_draw(void *v, int X, int Y, int, int) const {
       else fl_color(func_color);
       copy_trunc(buf, l->title(), 55, 0, 0);
     } else {
-      if (l->is_a(ID_Comment)) {
+      if (l->is_a(Type::Comment)) {
         // -- comment (in main line, not above entry)
         fl_font(comment_font, textsize());
         if (l->new_selected) fl_color(fl_contrast(comment_color, FL_SELECTION_COLOR));
@@ -458,7 +458,7 @@ int Node_Browser::item_width(void *v) const {
 
   char buf[500]; // edit buffer: large enough to hold 80 UTF-8 chars + nul
 
-  Fl_Type *l = (Fl_Type *)v;
+  Node *l = (Node *)v;
 
   if (!l->visible) return 0;
 
@@ -490,7 +490,7 @@ int Node_Browser::item_width(void *v) const {
  Callback to tell the Fluid UI when the list of selected items changed.
  */
 void Node_Browser::callback() {
-  selection_changed((Fl_Type*)selection());
+  selection_changed((Node*)selection());
 }
 
 /**
@@ -508,13 +508,13 @@ void Node_Browser::callback() {
  \return 0 if the event is not supported, and 1 if the event was "used up"
  */
 int Node_Browser::handle(int e) {
-  static Fl_Type *title;
-  Fl_Type *l;
+  static Node *title;
+  Node *l;
   int X,Y,W,H; bbox(X,Y,W,H);
   switch (e) {
   case FL_PUSH:
     if (!Fl::event_inside(X,Y,W,H)) break;
-    l = (Fl_Type*)find_item(Fl::event_y());
+    l = (Node*)find_item(Fl::event_y());
     if (l) {
       X += 3 + 12*l->level - hposition();
       if (l->can_have_children() && Fl::event_x()>X && Fl::event_x()<X+13) {
@@ -526,11 +526,11 @@ int Node_Browser::handle(int e) {
     break;
   case FL_DRAG:
     if (!title) break;
-    l = (Fl_Type*)find_item(Fl::event_y());
+    l = (Node*)find_item(Fl::event_y());
     if (l) {
       X += 3 + 12*l->level - hposition();
       if (l->can_have_children() && Fl::event_x()>X && Fl::event_x()<X+13) ;
-      else l = 0;
+      else l = nullptr;
     }
     if (l != pushedtitle) {
       if (pushedtitle) redraw_line(pushedtitle);
@@ -540,7 +540,7 @@ int Node_Browser::handle(int e) {
     return 1;
   case FL_RELEASE:
     if (!title) {
-      l = (Fl_Type*)find_item(Fl::event_y());
+      l = (Node*)find_item(Fl::event_y());
       if (l && l->new_selected && (Fl::event_clicks() || Fl::event_state(FL_CTRL)))
         l->open();
       break;
@@ -550,14 +550,14 @@ int Node_Browser::handle(int e) {
     if (l) {
       if (!l->folded_) {
         l->folded_ = 1;
-        for (Fl_Type*k = l->next; k&&k->level>l->level; k = k->next)
+        for (Node*k = l->next; k&&k->level>l->level; k = k->next)
           k->visible = 0;
       } else {
         l->folded_ = 0;
-        for (Fl_Type*k=l->next; k&&k->level>l->level;) {
+        for (Node*k=l->next; k&&k->level>l->level;) {
           k->visible = 1;
           if (k->can_have_children() && k->folded_) {
-            Fl_Type *j;
+            Node *j;
             for (j = k->next; j && j->level>k->level; j = j->next) {/*empty*/}
             k = j;
           } else
@@ -602,9 +602,9 @@ void Node_Browser::rebuild() {
 
 /**
  Rebuild the browser layout and make sure that the given item is visible.
- \param[in] inNode pointer to a widget node derived from Fl_Type.
+ \param[in] inNode pointer to a widget node derived from Node.
  */
-void Node_Browser::display(Fl_Type *inNode) {
+void Node_Browser::display(Node *inNode) {
   if (!inNode) {
     // Alternative: find the first (last?) visible selected item.
     return;
@@ -613,7 +613,7 @@ void Node_Browser::display(Fl_Type *inNode) {
   int currentV = vposition(), newV = currentV;
   int nodeV = 0;
   // find the inNode in the tree and check, if it is already visible
-  Fl_Type *p=Fl_Type::first;
+  Node *p=Fluid.proj.tree.first;
   for ( ; p && p!=inNode; p=p->next) {
     if (p->visible)
       nodeV += item_height(p) + linespacing();
@@ -640,7 +640,7 @@ void Node_Browser::display(Fl_Type *inNode) {
 
 void Node_Browser::load_prefs() {
   int c;
-  Fl_Preferences p(fluid_prefs, "widget_browser");
+  Fl_Preferences p(Fluid.preferences, "widget_browser");
   p.get("label_color",  c, 72); label_color = c;
   p.get("label_font",   c, FL_HELVETICA); label_font = c;
   p.get("class_color",  c, FL_FOREGROUND_COLOR); class_color = c;
@@ -656,7 +656,7 @@ void Node_Browser::load_prefs() {
 }
 
 void Node_Browser::save_prefs() {
-  Fl_Preferences p(fluid_prefs, "widget_browser");
+  Fl_Preferences p(Fluid.preferences, "widget_browser");
   p.set("label_color",    (int)label_color);
   p.set("label_font",     (int)label_font);
   p.set("class_color",    (int)class_color);
diff --git a/fluid/widgets/Node_Browser.h b/fluid/widgets/Node_Browser.h
index 5ac74b50a..eec1e7960 100644
--- a/fluid/widgets/Node_Browser.h
+++ b/fluid/widgets/Node_Browser.h
@@ -1,5 +1,5 @@
 //
-// Widget Browser code for the Fast Light Tool Kit (FLTK).
+// Widget Tree Browser code for the Fast Light Tool Kit (FLTK).
 //
 // Copyright 1998-2025 by Bill Spitzak and others.
 //
@@ -19,20 +19,20 @@
 
 #include <FL/Fl_Browser_.H>
 
-class Fl_Type;
+class Node;
 
 namespace fld {
 namespace widget {
 
 class Node_Browser : public Fl_Browser_
 {
-  friend class Fl_Type;
+  friend class Node;
 
   static void callback_stub(Fl_Widget *o, void *) {
     ((Node_Browser *)o)->callback();
   }
 
-  Fl_Type* pushedtitle { nullptr };
+  Node* pushedtitle { nullptr };
   int saved_h_scroll_ { 0 };
   int saved_v_scroll_ { 0 };
 
@@ -55,7 +55,7 @@ public:
   void restore_scroll_position();
   void rebuild();
   void new_list() { Fl_Browser_::new_list(); }
-  void display(Fl_Type *);
+  void display(Node *);
   void load_prefs();
   void save_prefs();
 
@@ -78,11 +78,11 @@ public:
 
 extern void redraw_browser();
 extern Fl_Widget *make_widget_browser(int x,int y,int w,int h);
-extern void redraw_widget_browser(Fl_Type *caller);
-extern void select(Fl_Type *o, int v);
-extern void select_only(Fl_Type *o);
+extern void redraw_widget_browser(Node *caller);
+extern void select(Node *o, int v);
+extern void select_only(Node *o);
 extern void deselect();
-extern void reveal_in_browser(Fl_Type *t);
+extern void reveal_in_browser(Node *t);
 
 extern fld::widget::Node_Browser *widget_browser;
 
diff --git a/fluid/widgets/Text_Viewer.cxx b/fluid/widgets/Text_Viewer.cxx
index ba2d145fe..5ae821d6b 100644
--- a/fluid/widgets/Text_Viewer.cxx
+++ b/fluid/widgets/Text_Viewer.cxx
@@ -1,6 +1,5 @@
 //
-// Code editor widget for the Fast Light Tool Kit (FLTK).
-// Syntax highlighting rewritten by erco@seriss.com 09/15/20.
+// Text Viewer widget for the Fast Light Tool Kit (FLTK).
 //
 // Copyright 1998-2025 by Bill Spitzak and others.
 //
@@ -40,7 +39,7 @@ Text_Viewer::Text_Viewer(int X, int Y, int W, int H, const char *L)
  */
 Text_Viewer::~Text_Viewer() {
   Fl_Text_Buffer *buf = mBuffer;
-  buffer(0);
+  buffer(nullptr);
   delete buf;
 }
 
diff --git a/fluid/widgets/Text_Viewer.h b/fluid/widgets/Text_Viewer.h
index 1e5810d50..98fa9200f 100644
--- a/fluid/widgets/Text_Viewer.h
+++ b/fluid/widgets/Text_Viewer.h
@@ -1,6 +1,5 @@
 //
-// Code editor widget for the Fast Light Tool Kit (FLTK).
-// Syntax highlighting rewritten by erco@seriss.com 09/15/20.
+// Text Viewer widget for the Fast Light Tool Kit (FLTK).
 //
 // Copyright 1998-2025 by Bill Spitzak and others.
 //