Fix problem dropping files when a popup window is opened.

src/drop_files.cpp

@@ -21,13 +21,13 @@
 #include <allegro.h>
 #include <vector>
 
-#include "gui/frame.h"
-
 #include "app.h"
 #include "base/mutex.h"
 #include "base/scoped_lock.h"
 #include "commands/commands.h"
 #include "commands/params.h"
+#include "gui/frame.h"
+#include "gui/manager.h"
 #include "ui_context.h"
 
 #ifdef ALLEGRO_WINDOWS
@@ -73,7 +73,9 @@ void check_for_dropped_files()
   if (!base_wnd_proc)           // drop-files hook not installed
     return;
 
-  if (!app_get_top_window()->is_toplevel())
+  // If the main window is not the current foreground one. We discard
+  // the drop-files event.
+  if (jmanager_get_foreground_window() != app_get_top_window())
     return;
 
   ScopedLock lock(*dropped_files_mutex);

src/gui/manager.cpp

@@ -723,6 +723,18 @@ JWidget jmanager_get_top_window()
     return NULL;
 }
 
+JWidget jmanager_get_foreground_window()
+{
+  JLink link;
+  JI_LIST_FOR_EACH(default_manager->children, link) {
+    Frame* frame = (Frame*)link->data;
+    if (frame->is_foreground() ||
+        frame->is_desktop())
+      return frame;
+  }
+  return NULL;
+}
+
 JWidget jmanager_get_focus()
 {
   return focus_widget;

src/gui/manager.h

@@ -34,6 +34,7 @@ bool jmanager_timer_is_running(int timer_id);
 void jmanager_enqueue_message(Message* msg);
 
 JWidget jmanager_get_top_window();
+JWidget jmanager_get_foreground_window();
 
 JWidget jmanager_get_focus();
 JWidget jmanager_get_mouse();