add fallback icons

src/plugins/domain/raction.py

@@ -80,8 +80,8 @@ class RAction():
         action.setText(self.label)
         self._action = action
         if self.icon_from_theme:
-            action.setIcon(Icon.fromTheme(self.icon_from_theme))
-        if self.icon_file:
+            action.setIcon(Icon.fromTheme(self.icon_from_theme, self.icon_file))
+        elif self.icon_file:
             action.setIcon(Icon(self.icon_file))
         if self.shortcut:
             action.setShortcut(self.shortcut)

src/plugins/openfileplugin.py

@@ -23,6 +23,7 @@ class OpenFilePlugin(PluginBase):
 
     def _action_open_file(self) -> RAction:
         open_file = RAction(_("&Open..."), self._open_file_dialog, shortcut='Ctrl+O',
+                            icon_from_theme="fileopen",
                             icon_file="icons/myicons/select-file.svg")
         return open_file