scroll key sometimes stuck

[Mailaender]

When I use the keyboard for scrolling sometimes the arrow feels "stuck" as I endlessly scroll into 1 direction. When I press the opposite key the scrolling simply stops instead of going into the different direction. I can only navigate via radar or backspace (to HQ) then. It vanishes after sometime, but it is really annoying. Happens often, but hard to reproduce.

[earthpig]

This happens to me fairly often too, now that I think about it. Mashing the arrow keys a few times each seems to make it go away; I guess I don't even notice it any more. :\

[ScottNZ]

Just came up with a repro:

1. hold down an arrow key to scroll
2. drag a box with your mouse while you're scrolling
3. release the arrow key but keep your mouse down
4. release mouse button

[cjshmyr]

Easy to repo with Scott's method

[abcdefg30]

I can reproduce this on latest bleed.

New repo case:

1. Press an arrow key and hold it
2. Press esc
3. Release the arrow key
4. Press esc again

[rob-v]

IMO #13111 = this issue #2075, solved by PR #13115 (occurs in game)
@ScottNZ's repro was solved by @pchote

@abcdefg30 case - can still be reproduced, but is minor - you need to keep arrow key pressed and press ESC. when you return to game, simple 1 key press (in the broken direction) fixes it. The other 2 issues weren't solved by simple key press, it was real issue in game, this is minor.
We would need to inform Viewport that such an event occurred to cancel scrolling. If there is no such event atm, we can simply keep it as is and close this issue after merging PR #13115.