Restore the "Position" section in Timeline configuration

We're going to keep this section for a couple of versions as old users
get used to the new Workspace Layout customization.

The "Position" section will contain the layout icon so we can switch
the Workspace Layout combobox from there too,

src/app/file/gif_format.cpp

@@ -1095,6 +1095,9 @@ public:
     gifframe_t nframes = totalFrames();
     for (gifframe_t gifFrame = 0; gifFrame < nframes; ++gifFrame) {
       ASSERT(frame_it != frame_end);
+      if (m_fop->isStop())
+        break;
+
       frame_t frame = *frame_it;
       ++frame_it;
 

src/app/script/dialog_class.cpp

@@ -127,12 +127,13 @@ struct Dialog {
   int showRef = LUA_REFNIL;
   lua_State* L = nullptr;
 
-  Dialog(const ui::Window::Type windowType, const std::string& title)
+  Dialog(const ui::Window::Type windowType, const std::string& title, bool sizeable)
     : window(windowType, title)
     , grid(2, false)
     , currentGrid(&grid)
   {
     window.addChild(&grid);
+    window.setSizeable(sizeable);
     all_dialogs.push_back(this);
   }
 
@@ -365,6 +366,7 @@ int Dialog_new(lua_State* L)
   // Get the title and the type of window (with or without title bar)
   ui::Window::Type windowType = ui::Window::WithTitleBar;
   std::string title = "Script";
+  bool sizeable = true;
   if (lua_isstring(L, 1)) {
     title = lua_tostring(L, 1);
   }
@@ -378,9 +380,14 @@ int Dialog_new(lua_State* L)
     if (type != LUA_TNIL && lua_toboolean(L, -1))
       windowType = ui::Window::WithoutTitleBar;
     lua_pop(L, 1);
+
+    type = lua_getfield(L, 1, "resizeable");
+    if (type != LUA_TNIL && !lua_toboolean(L, -1))
+      sizeable = false;
+    lua_pop(L, 1);
   }
 
-  auto dlg = push_new<Dialog>(L, windowType, title);
+  auto dlg = push_new<Dialog>(L, windowType, title, sizeable);
 
   // The uservalue of the dialog userdata will contain a table that
   // stores all the callbacks to handle events. As these callbacks can
@@ -1509,6 +1516,10 @@ int Dialog_modify(lua_State* L)
     type = lua_getfield(L, 2, "text");
     if (const char* s = lua_tostring(L, -1)) {
       widget->setText(s);
+
+      // Re-process mnemonics for buttons
+      if (widget->type() == WidgetType::kButtonWidget)
+        widget->processMnemonicFromText();
       relayout = true;
     }
     lua_pop(L, 1);

src/app/script/plugin_class.cpp

@@ -172,6 +172,7 @@ int Plugin_newCommand(lua_State* L)
       if (!group.empty() && App::instance()->isGui()) { // On CLI menus do not make sense
         if (auto appMenus = AppMenus::instance()) {
           auto menuItem = std::make_unique<AppMenuItem>(title, id);
+          menuItem->processMnemonicFromText();
           appMenus->addMenuItemIntoGroup(group, std::move(menuItem));
         }
       }