xdg-desktop-portal RemoteDesktop missing modifier key support

[ehaufler]

In the RemoteDesktop portal interface-methods
NotifyPointerButton
NotifyKeyboardKeycode
NotifyKeyboardKeysym
(probably some other methods as well)
I don't find "modifier" keys or a modifier mask of pressed shift / ctrl / alt keys.

We would need modifiers e.g. to handle cursor left (moves a cursor in the editor) versus shift + cursor left (mark text);
or difference of mouse-click and move vs. shift+mouse-click and move.

One could track e.g. the Shift-Key itself (pressed and released), but this is not reliable, as the shift key may have been pressed before the relevant window has got the keyboard focus. Or Caps-Lock would not be recognized.

Is there already a possibility to distinguish the shift / ctrl / alt state ? (I thought about adding an "option", but so far no option is defined for that). Could a "modifierMask" property be added to these interfaces?

Thanks for any answers!
Eckart