Index: src/dlg-crop.c
===================================================================
--- src/dlg-crop.c	(revision 2085)
+++ src/dlg-crop.c	(working copy)
@@ -482,6 +482,7 @@
 	GthCropRatio  crop_ratio;
 	int           ratio_w, ratio_h;
 	GdkScreen    *screen;
+	GdkRectangle  screen_geom;
 
 	data = g_new0 (DialogData, 1);
 	data->window = window;
@@ -688,10 +689,17 @@
 
 	gtk_widget_realize (data->dialog);
 
-	screen = gdk_screen_get_default();
+	/* Get screen parent window is on. */
+	screen = gtk_widget_get_screen(GTK_WIDGET (window));
+
+	/* Get x,y,width,height of *monitor* parent window's GdkWindow is on. */
+	gdk_screen_get_monitor_geometry (screen,
+			gdk_screen_get_monitor_at_window (screen, GTK_WIDGET(window)->window),
+			&screen_geom);
+
 	gtk_window_set_default_size (GTK_WINDOW (data->dialog),
-				     gdk_screen_get_width (screen) * 7 / 10,
-				     gdk_screen_get_height (screen) * 6 / 10);
+				     screen_geom.width * 7 / 10,
+				     screen_geom.height * 6 / 10);
 
 	gth_iviewer_zoom_to_fit (GTH_IVIEWER (data->image_selector));
 	gtk_widget_grab_focus (data->image_selector);
