2 files changed, 18 insertions, 0 deletions
diff --git a/fluid/custom_widgets.cxx b/fluid/custom_widgets.cxx
index 170ef44a2..f409e9761 100644
--- a/fluid/custom_widgets.cxx
+++ b/fluid/custom_widgets.cxx
@@ -292,3 +292,19 @@ void Fluid_Coord_Input::value(int v) {
   fl_snprintf(buf, sizeof(buf), "%d", v);
   text(buf);
 }
+
+/**
+ Allow vertical mouse dragging and mouse wheel to interactively change the value.
+ */
+int Fluid_Coord_Input::handle(int event) {
+  switch (event) {
+    case FL_MOUSEWHEEL:
+      if (Fl::event_dy()) {
+        value( value() - Fl::event_dy() );
+        set_changed();
+        do_callback(FL_REASON_CHANGED);
+      }
+      return 1;
+  }
+  return Fl_Input::handle(event);
+}
diff --git a/fluid/custom_widgets.h b/fluid/custom_widgets.h
index 8a464ae82..36abc1414 100644
--- a/fluid/custom_widgets.h
+++ b/fluid/custom_widgets.h
@@ -83,6 +83,8 @@ public:
     vars_ = vars;
     vars_user_data_ = user_data;
   }
+
+  int handle(int) override;
 };
 
 #endif