inspector: Use a separate display connection

This helps isolate the inspector from some of the changes that
it can trigger. To specify a different display, set
GTK_INSPECTOR_DISPLAY to the name of the display to use for
the inspector window. If no display is specified, GTK+ will
use a separate connection to the default display.

gtk/inspector/general.c

@@ -70,7 +70,7 @@ init_version (GtkInspectorGeneral *gen)
   const gchar *backend;
   GdkDisplay *display;
 
-  display = gtk_widget_get_display (GTK_WIDGET (gen));
+  display = gdk_display_get_default ();
 
 #ifdef GDK_WINDOWING_X11
   if (GDK_IS_X11_DISPLAY (display))

gtk/inspector/inspect-button.c

@@ -29,6 +29,7 @@
 
 #include "gtkstack.h"
 #include "gtkmain.h"
+#include "gtkinvisible.h"
 
 typedef struct
 {
@@ -312,21 +313,39 @@ gtk_inspector_on_inspect (GtkWidget          *button,
   GdkDisplay *display;
   GdkDevice *device;
   GdkCursor *cursor;
+  GdkGrabStatus status;
 
-  g_signal_connect (button, "event",
-                    G_CALLBACK (property_query_event), iw);
+  if (!iw->invisible)
+    {
+      iw->invisible = gtk_invisible_new_for_screen (gdk_screen_get_default ());
+      gtk_widget_add_events (iw->invisible,
+                             GDK_POINTER_MOTION_MASK |
+                             GDK_BUTTON_PRESS_MASK |
+                             GDK_BUTTON_RELEASE_MASK |
+                             GDK_KEY_PRESS_MASK |
+                             GDK_KEY_RELEASE_MASK);
+      gtk_widget_realize (iw->invisible);
+      gtk_widget_show (iw->invisible);
+    }
 
-  display = gtk_widget_get_display (button);
+  display = gdk_display_get_default ();
   cursor = gdk_cursor_new_for_display (display, GDK_CROSSHAIR);
   device = gdk_device_manager_get_client_pointer (gdk_display_get_device_manager (display));
-  gdk_device_grab (device,
-                   gtk_widget_get_window (GTK_WIDGET (button)),
-                   GDK_OWNERSHIP_NONE, TRUE,
-                   GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK,
-                   cursor, GDK_CURRENT_TIME);
+  status = gdk_device_grab (device,
+                            gtk_widget_get_window (iw->invisible),
+                            GDK_OWNERSHIP_NONE, TRUE,
+                            GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK,
+                            cursor, GDK_CURRENT_TIME);
   g_object_unref (cursor);
-  gtk_grab_add (GTK_WIDGET (button));
+  if (status != GDK_GRAB_SUCCESS)
+    {
+      g_warning ("grab failed (%d) :-(\n", status); 
+      return;
+    }
 
+  g_signal_connect (iw->invisible, "event", G_CALLBACK (property_query_event), iw);
+
+  gtk_grab_add (GTK_WIDGET (iw->invisible));
   gdk_window_lower (gtk_widget_get_window (GTK_WIDGET (iw)));
 }
 
@@ -419,7 +438,7 @@ gtk_inspector_window_select_widget_under_pointer (GtkInspectorWindow *iw)
   GdkDevice *device;
   GtkWidget *widget;
 
-  display = gtk_widget_get_display (GTK_WIDGET (iw));
+  display = gdk_display_get_default ();
   dm = gdk_display_get_device_manager (display);
   device = gdk_device_manager_get_client_pointer (dm);
 

gtk/inspector/object-tree.c

@@ -526,6 +526,7 @@ gtk_inspector_object_tree_scan (GtkInspectorObjectTree *wt,
 {
   GtkWidget *inspector_win;
   GList *toplevels, *l;
+  GdkScreen *screen;
 
   gtk_tree_store_clear (wt->priv->model);
   g_hash_table_remove_all (wt->priv->iters);
@@ -536,12 +537,15 @@ gtk_inspector_object_tree_scan (GtkInspectorObjectTree *wt,
   if (window)
     gtk_inspector_object_tree_append_object (wt, G_OBJECT (window), NULL, NULL);
 
+  screen = gdk_screen_get_default ();
+
   inspector_win = gtk_widget_get_toplevel (GTK_WIDGET (wt));
   toplevels = gtk_window_list_toplevels ();
   for (l = toplevels; l; l = l->next)
     {
       if (GTK_IS_WINDOW (l->data) &&
           gtk_window_get_window_type (l->data) == GTK_WINDOW_TOPLEVEL &&
+          gtk_widget_get_screen (l->data) == screen &&
           l->data != window &&
           l->data != inspector_win)
         gtk_inspector_object_tree_append_object (wt, G_OBJECT (l->data), NULL, NULL);

gtk/inspector/visual.c

@@ -361,7 +361,7 @@ scale_changed (GtkAdjustment *adjustment, GtkInspectorVisual *vis)
   gint scale;
 
   scale = gtk_adjustment_get_value (adjustment);
-  display = gtk_widget_get_display (GTK_WIDGET (vis));
+  display = gdk_display_get_default ();
   gdk_x11_display_set_window_scale (display, scale);
 }
 #endif
@@ -372,7 +372,7 @@ init_scale (GtkInspectorVisual *vis)
 #if defined (GDK_WINDOWING_X11) && defined (HAVE_CAIRO_SURFACE_SET_DEVICE_SCALE)
   GdkScreen *screen;
 
-  screen = gtk_widget_get_screen (GTK_WIDGET (vis));
+  screen = gdk_screen_get_default ();
   if (GDK_IS_X11_SCREEN (screen))
     {
       gdouble scale;

gtk/inspector/window.c

@@ -175,10 +175,45 @@ gtk_inspector_window_class_init (GtkInspectorWindowClass *klass)
   gtk_widget_class_bind_template_callback (widget_class, close_details);
 }
 
+static GdkScreen *
+get_inspector_screen (void)
+{
+  static GdkDisplay *display = NULL;
+
+  if (display == NULL)
+    {
+      const gchar *name;
+
+      name = g_getenv ("GTK_INSPECTOR_DISPLAY");
+      display = gdk_display_open (name);
+
+      if (display)
+        g_debug ("Using display %s for GtkInspector", name);
+      else
+        g_message ("Failed to open display %s", name);
+    }
+
+  if (!display)
+    {
+      display = gdk_display_open (NULL);
+      if (display)
+        g_debug ("Using default display for GtkInspector");
+      else
+        g_message ("Failed to separate connection to default display");
+    }
+
+  if (!display)
+    display = gdk_display_get_default ();
+
+  return gdk_display_get_default_screen (display);
+}
+
 GtkWidget *
 gtk_inspector_window_new (void)
 {
-  return GTK_WIDGET (g_object_new (GTK_TYPE_INSPECTOR_WINDOW, NULL));
+  return GTK_WIDGET (g_object_new (GTK_TYPE_INSPECTOR_WINDOW,
+                                   "screen", get_inspector_screen (),
+                                   NULL));
 }
 
 // vim: set et sw=2 ts=2:

gtk/inspector/window.h

@@ -63,6 +63,7 @@ typedef struct
   GtkWidget *misc_info;
   GtkWidget *gestures;
 
+  GtkWidget *invisible;
   GtkWidget *selected_widget;
   GtkWidget *flash_widget;