xtt: Fix subwindow segfault when updating context

xtt/lib/glow/gtk/glow_draw_gtk.cpp

@@ -4156,9 +4156,14 @@ void GlowDrawGtk::pop_customcolors()
 {
   if (customcolors_cnt <= 0) {
     printf("** Customcolor stack disorder\n");
+    return;
   }
+
   for (int i = 0; i < customcolors_cnt - 1; i++)
+  {
     customcolors[i] = customcolors[i + 1];
+    customcolors[i + 1] = NULL;
+  }
   customcolors_cnt--;
 }
 

xtt/lib/glow/src/glow_growwindow.cpp

@@ -789,12 +789,13 @@ int GrowWindow::update_attributes()
     if (window_ctx) {
       if (window_ctx->trace_started)
         window_ctx->trace_close();
+      ctx->gdraw->pop_customcolors();
       delete window_ctx;
       fill_drawtype = original_fill_drawtype = glow_eDrawType_Inherit;
       fill = 0;
     }
     strcpy(file_name, input_file_name);
-    new_ctx();
+    new_ctx(true);
     sts = 1;
 
     ctx->gdraw->reset_clip_rectangle(&ctx->mw);
@@ -923,7 +924,7 @@ void GrowWindow::h_value_changed_cb(void* o, double value)
   gw->draw();
 }
 
-void GrowWindow::new_ctx()
+void GrowWindow::new_ctx(bool is_updating_attributes)
 {
   char fname[200];
   int sts;
@@ -976,6 +977,9 @@ void GrowWindow::new_ctx()
   if (!copied)
     strcpy(window_ctx->owner, owner);
   window_ctx->customcolors = ctx->gdraw->create_customcolors();
+  
+  if (is_updating_attributes)
+    ctx->gdraw->push_customcolors(window_ctx->customcolors);
 
   if (!no_file) {
     window_ctx->set_nodraw();

xtt/lib/glow/src/glow_growwindow.h

@@ -278,7 +278,7 @@ public:
   int update_attributes();
 
   //! Create a new grow context
-  void new_ctx();
+  void new_ctx(bool is_updating_attributes = false);
 
   // Configure the scrollbars
   void configure_scrollbars();