please implement all of the choosable taskbar doubleclick options to the tray icon left-click settings in the tray right-click menu.

i have usually no empty space on my taskbar to click

There's the "Reserve empty space on taskbar" option just for that.

You can also configure a keyboard hotkey for this, or configure a custom mouse hotkey for the "show desktop" button (e.g. Shift+click or middle click).

That's not exactly what you've asked for, just mentioning other options.

I'm sure i tried yesterday the "Reserve empty space on taskbar" option too, but not really worked.

Strangely today works. I dont know why. Maybe some open task combination or other setting's combination confused that.

I hope it remains working continuously. Thank you!