Is there any way to bring up the
keepassX window when the application is started but the window is hidden? I mean that the application is running but only the icon in the notification area is visible. Is there any way to do this? Is there any way to configure a shortcut?
Not strictly an answer for KeepassX and kind of a workaround...
I tend to use
xdotool in those cases, it's great for window tinkering and automation.
You could do something like
xdotool search --name keepassX windowactivate
Just make sure
--name is the same as the window title.
And then make a keyboard shortcut to that command or put it in Keepass's launcher.
I had a similar issue and made an open-source solution based on xdotool for that.
After install, click on the "HK" icon in the tray, then add a macro. Choose "Window Pin by name". Click on the gear next to it and type 'KeePassX'. Then click on the pen to set your shortcut.
Personally, I'm using ALT+P to bring KeePassX on the foreground. The app must be already running, however. So I made it start on boot.