gtk4-prep: restore right-click node popup and alt+scroll channel tab switching

src/bauhaus/bauhaus.c

@@ -3333,6 +3333,27 @@ static void _popup_show(GtkWidget *widget)
   gtk_widget_grab_focus(pop->area);
 }
 
+/** open the value-entry popup of a bauhaus widget, as if it were right-clicked.
+ *  GTK4: gtk_get_current_event() is gone; when porting, read the time from
+ *  the gesture's last event instead (gtk_gesture_get_last_event()). */
+void dt_bauhaus_widget_show_popup(GtkWidget *widget)
+{
+  dt_bauhaus_widget_t *w = DT_BAUHAUS_WIDGET(widget);
+  dt_bauhaus_t *bh = darktable.bauhaus;
+
+  if(w->type == DT_BAUHAUS_TOGGLE) return;
+
+  GdkEvent *event = gtk_get_current_event();
+  if(event)
+  {
+    bh->opentime = gdk_event_get_time(event);
+    gdk_event_free(event);
+  }
+  bh->mouse_x = 0;
+  bh->mouse_y = 0;
+  _popup_show(widget);
+}
+
 static void _slider_add_step(GtkWidget *widget,
                              float delta,
                              const guint state,

src/bauhaus/bauhaus.h

@@ -1,6 +1,6 @@
 /*
     This file is part of darktable,
-    Copyright (C) 2012-2025 darktable developers.
+    Copyright (C) 2012-2026 darktable developers.
 
     darktable is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -195,6 +195,10 @@ const char* dt_bauhaus_widget_get_label(GtkWidget *widget);
 void dt_bauhaus_widget_hide_label(GtkWidget *widget);
 void dt_bauhaus_widget_set_show_extended_label(GtkWidget *widget,
                                                gboolean show);
+// open the value-entry popup of a bauhaus widget, as if it were right-clicked.
+// Used by callers that want the popup without sending the widget a synthetic
+// button press (which a gesture-based widget cannot handle cleanly)
+void dt_bauhaus_widget_show_popup(GtkWidget *widget);
 void dt_bauhaus_widget_set_module(GtkWidget *widget,
                                   dt_action_t *module);
 gpointer dt_bauhaus_widget_get_module(GtkWidget *widget);

src/iop/atrous.c

@@ -1531,7 +1531,14 @@ static void area_scrolled(GtkEventControllerScroll *controller,
 
   if(dt_modifier_eq(controller, GDK_MOD1_MASK))
   {
-    // FIXME: GTK4 - need to forward scroll event to notebook
+    // alt+scroll switches the channel tab (as before the controller conversion)
+    // GTK4: no gtk_widget_event() -- reimplement as a controller on the notebook
+    GdkEvent *event = gtk_get_current_event();
+    if(event)
+    {
+      gtk_widget_event(GTK_WIDGET(g->channel_tabs), event);
+      gdk_event_free(event);
+    }
     return;
   }
 

src/iop/colorequal.c

@@ -2761,7 +2761,17 @@ static void _area_button_press_callback(GtkGestureSingle *gesture,
     else
       g->dragging = TRUE;
   }
-  // other buttons: forward not supported with event controllers, ignored
+  else
+  {
+    // other buttons (e.g. right-click): open the value-entry popup of the
+    // selected node's slider.  The old button-press-event handler forwarded
+    // the event to the slider widget; a gesture-based bauhaus widget cannot
+    // be fed a synthetic press (the unmatched release would leave its
+    // gesture with a stale sequence), so open the popup directly.  Claim the
+    // event so it does not bubble up to the module menu.
+    dt_bauhaus_widget_show_popup(_get_slider(g, g->selected));
+    dt_gui_claim(gesture);
+  }
 }
 
 static void _area_button_release_callback(GtkGestureSingle *gesture,
@@ -2771,8 +2781,9 @@ static void _area_button_release_callback(GtkGestureSingle *gesture,
                                            dt_iop_module_t *self)
 {
   dt_iop_colorequal_gui_data_t *g = self->gui_data;
+  const guint button = gtk_gesture_single_get_current_button(gesture);
 
-  if(gtk_gesture_single_get_current_button(gesture) == GDK_BUTTON_PRIMARY)
+  if(button == GDK_BUTTON_PRIMARY)
     g->dragging = FALSE;
 }
 

src/iop/colorzones.c

@@ -1867,7 +1867,14 @@ static void _area_scrolled_callback(GtkEventControllerScroll *controller,
 
   if(dt_modifier_is(dt_key_modifier_state(), GDK_MOD1_MASK))
   {
-    // FIXME: event forwarding to g->channel_tabs removed
+    // alt+scroll switches the channel tab (as before the controller conversion)
+    // GTK4: no gtk_widget_event() -- reimplement as a controller on the notebook
+    GdkEvent *event = gtk_get_current_event();
+    if(event)
+    {
+      gtk_widget_event(GTK_WIDGET(g->channel_tabs), event);
+      gdk_event_free(event);
+    }
     return;
   }
 

src/iop/denoiseprofile.c

@@ -3543,6 +3543,22 @@ static void denoiseprofile_scrolled(GtkEventControllerScroll *controller,
 {
   dt_iop_denoiseprofile_gui_data_t *g = self->gui_data;
 
+  if(dt_modifier_eq(controller, GDK_MOD1_MASK))
+  {
+    // alt+scroll switches the channel tab (as before the controller conversion)
+    // GTK4: no gtk_widget_event() -- reimplement as a controller on the notebook
+    GdkEvent *event = gtk_get_current_event();
+    if(event)
+    {
+      gtk_widget_event(GTK_WIDGET(g->channel > DT_DENOISE_PROFILE_B
+                                  ? g->channel_tabs_Y0U0V0
+                                  : g->channel_tabs),
+                       event);
+      gdk_event_free(event);
+    }
+    return;
+  }
+
   if(dy != 0.0)
   {
     g->mouse_radius = CLAMP(g->mouse_radius * (1.f - 0.1f * dy),

src/iop/rawdenoise.c

@@ -850,6 +850,19 @@ static void rawdenoise_scrolled(GtkEventControllerScroll *controller, gdouble dx
 {
   dt_iop_rawdenoise_gui_data_t *g = self->gui_data;
 
+  if(dt_modifier_eq(controller, GDK_MOD1_MASK))
+  {
+    // alt+scroll switches the channel tab (as before the controller conversion)
+    // GTK4: no gtk_widget_event() -- reimplement as a controller on the notebook
+    GdkEvent *event = gtk_get_current_event();
+    if(event)
+    {
+      gtk_widget_event(GTK_WIDGET(g->channel_tabs), event);
+      gdk_event_free(event);
+    }
+    return;
+  }
+
   if(dy != 0.0)
   {
     g->mouse_radius = CLAMP(g->mouse_radius * (1.0 - 0.1 * dy), 0.2 / DT_IOP_RAWDENOISE_BANDS, 1.0);