Global hotkey to open/close from/to system tray

[GennDALF]

Is it possible to add a global system hotkey that will open the main window from the system tray and close it to the system tray? I mean the behaviour like NumLock Calc has.

The scenario is to load Qalculate! with the OS and keep it in the tray, but open/close whenever you need it.

[hanna-kn]

Currently this is possible:
Use Escape or general shortcut (e.g. Alt+F4) to close the window.
Run qalculate-gtk to open the window. Assign a key using a keyboard shortcut application of your choice.

[hanna-kn]

My suggestion is that I add a command line option, for use with hotkey programs, which toggles visibility of qalculate-gtk windows.

[GennDALF]

Assign a key using a keyboard shortcut application of your choice.

What I would like to avoid is a keyboard shortcut application. For many reasons.

Isn't it possible for you to add a system shortcut to the qalculate itself?