Ingame mouse cursor stuck when the menu is opened

[oxiKKK]

Describe the bug
There's a scenario where if you are in fullscreen mode, and you alt+tab out of the window with the menu opened, the mouse cursor gets stucked in the center of the UI and wont move.

To Reproduce
Start the game in fullscreen, go to a server, possibly also set m_rawinput to 1, open up the UI (menu), alt+tab out of the window, focus on another window by clicking at it, go back into the game. The mouse cursor should be then suck.

Note that this can be resolved by closing the UI (menu), opening the ingame UI (by pressing esc), and then opening the cheat menu back. This resolves the issue.

Operating System
Windows 10

Version of the game (output of the version console command)

Protocol version 48
Exe version 1.1.2.7/Stdio (cstrike)
Exe build: 19:53:27 Aug  3 2020 (8684)