1 files changed, 32 insertions, 8 deletions

diff --git a/fluid/panels/widget_panel.cxx b/fluid/panels/widget_panel.cxx
index 5bbde2fec..5556a19fa 100644
--- a/fluid/panels/widget_panel.cxx
+++ b/fluid/panels/widget_panel.cxx
@@ -31,6 +31,7 @@
 #include <FL/fl_ask.H>
 #include <FL/Fl_Menu_Item.H>
 #include <FL/Fl_File_Chooser.H>
+#include <ctype.h>
 #define ZERO_ENTRY 1000
 extern const char* when_symbol_name(int n);
 extern void set_whenmenu(int n);
@@ -2636,11 +2637,10 @@ static void cb_Attribute(Fl_Input* o, void* v) {
   Class_Node* nd = (Class_Node*)current_node;
 
   if (v == LOAD) {
-    o->value( nd->prefix() );
+    o->value( nd->prefix().c_str() );
   } else {
-    const char *nn = nd->prefix();
-    if (   ( nn && (strcmp(nn, o->value()) != 0))
-        || (!nn && (strcmp("", o->value()) != 0)) )
+    auto nn = nd->prefix();
+    if (nn != o->value())
     {
       nd->prefix( o->value() );
       Fluid.proj.set_modflag(1);
@@ -2657,13 +2657,37 @@ static void cb_Class(Fl_Input* o, void* v) {
     o->value( nd->name() );
   } else {
     const char *nn = nd->name();
-    if (   ( nn && (strcmp(nn, o->value()) != 0))
-        || (!nn && (strcmp("", o->value()) != 0)) )
+    char *nv = strdup( o->value() );
+    // There is an inconsistency in the project file reader, so this string
+    // must not coantain anything but alphanumeric and underscore characters.
+    char *s = (char*)nv;
+    char *d = (char*)nv;
+    while (*s) {
+      if (isalnum((unsigned char)*s) || *s == '_') {
+        *d++ = *s;
+      }
+      s++;
+    }
+    *d = 0;
+    // The class name must not be empty either
+    if (*nv == 0) {
+      free((void*)nv);
+      nv = strdup("MyClass");
+    }
+    // The class name may have changed, so update the widget
+    o->value( nv );
+    // Now copy the new name into the node if it changed
+    if (   ( nn && (strcmp(nn, nv) != 0))
+        || (!nn && (strcmp("", nv) != 0)) )
     {
-      nd->name( o->value() );
+      nd->name( nv );
       Fluid.proj.set_modflag(1);
       redraw_browser();
     }
+    // Don't forget to clean up
+    if (nv) {
+      free((void*)nv);
+    }
   }
 }
 
@@ -3239,6 +3263,7 @@ Fl_Double_Window* make_widget_panel() {
         widget_tabs->labelcolor(FL_BACKGROUND2_COLOR);
         widget_tabs->callback((Fl_Callback*)cb_widget_tabs);
         widget_tabs->when(FL_WHEN_NEVER);
+        widget_tabs->hide();
         { wp_gui_tab = new Fl_Group(10, 30, 400, 330, "GUI");
           wp_gui_tab->labelsize(11);
           wp_gui_tab->callback((Fl_Callback*)propagate_load);
@@ -4326,7 +4351,6 @@ Fl_Double_Window* make_widget_panel() {
         class_tabs->labelsize(11);
         class_tabs->labelcolor(FL_WHITE);
         class_tabs->callback((Fl_Callback*)cb_class_tabs);
-        class_tabs->hide();
         { class_tabs_main = new Fl_Group(10, 30, 400, 330, "Class");
           class_tabs_main->labelsize(11);
           class_tabs_main->callback((Fl_Callback*)propagate_load);