Missing mouse cursor after entering 'READ THIS!' help screen

[Hexereticdoom]

Hello, here is another small bug I've discovered lately in 3.5.1 release, but possibly(?) present in previous ones...

For example, when you start Ultimate Doom, FreeDoom Phase 1 or Heretic Shadow of the Serpent Riders IWADs, if you make click on READ THIS section from main menu (or INFO in Heretic case) to access the game's help screen, after closing it the mouse cursor dissapears totally from view, that is, the graphic arrow gets invisible. However, it is still possible to make click on other menu entries, as they're highlighted depending of mouse movements, but the cursor is completely missing until you restart GZDoom again.

Additional note: seems that this bug is only reproducible on Linux system, because testing it in a borrowed Windows laptop the cursor restablishes normally exiting the help screens. (My current and main OS is Linux Mint 19 Cinnamon edition, if that serves as a guide).

[Edward-san]

I can reproduce it only if the softpoly renderer is selected.