[TF2] See-through corners on some main menu screen textures

[Ashetf2]

Title. This bug has existed since forever

I found a fix for it. You basiclly need to change the "$translucent" parameter to

"$alphatest" 1
"$allowAlphaToCoverage" 1

For the classic Source window borders, the materials are "round_corner_ne" "round_corner_nw" "round_corner_se" "round_corner_sw" and probably "solid_background", all of them in materials/vgui/gfx/vgui
For the window with thick borders, the material is loadout_rect in materials/vgui

For example for loadout_rect

"UnlitGeneric"
{
      "$basetexture" "vgui\loadout_rect"
      //"$translucent" 1
      "$alphatest" 1
      "$allowAlphaToCoverage" 1
      //"$ignorez" 1 (I believe the $ignorez doesn't do anything so I guess it's not necessary to delete it)
}