Fix wl-clipboard messing with the dock

[ndr3www]

A temporary fix of wl-clipboard appearing in the running apps section (#2193) and causing a hidden dock to show up for a brief moment when launched.

The problem is caused by not only the wl-clipboard but also other short-lived programs stealing focus so, as proposed in #988 and #2064, it would be nice to take it further and implement an option to ignore apps specified by the user.

[3v1n0]

Sorry, custom code like this can't be accepted upstream.

I wonder if you can find a window type or class the application matches. Or if the app needs to be fixed

[ndr3www]

Well, that's the main problem. wl-clipboard has no window class or anything specific assiociated with it, I'm aware that the title matching is not a good solution, but couldn't think of anything better unfortunately.

[sergio-costas]

@ndr3www @3v1n0 Maybe delaying for half a second adding a new icon to the dock?

[3v1n0]

Bah, it could be a posisbility, but normally I'm not in love with delays since they're not fully predictable, so they may work by luck and depending on the environment.

[sergio-costas]

I fully agree with delays; unfortunately, in this case is the only solution, because the point is, precisely, that the window is created and deleted very quickly, so we should only show icons for windows that have been in the screen for a minimum amount of time, and don't add icons to those windows that are there for less time than that minimum.