This is a minor issue, but still a bit annoying at times.
In windowed mode, when moving the cursor out of the window, the mouse focus stays on whatever it was on last. If you then move the mouse back into the window and click, it clicks on wherever the mouse was before it left the window.
For example, put another window next to the quit button, then move the mouse over the quit button, and then move it from there out of the TF2 window onto the other one. The quit button stays highlighted. When you move the mouse back into the TF2 window in a completely different place and click, it will quit the game.
This is a minor issue, but still a bit annoying at times.
In windowed mode, when moving the cursor out of the window, the mouse focus stays on whatever it was on last. If you then move the mouse back into the window and click, it clicks on wherever the mouse was before it left the window.
For example, put another window next to the quit button, then move the mouse over the quit button, and then move it from there out of the TF2 window onto the other one. The quit button stays highlighted. When you move the mouse back into the TF2 window in a completely different place and click, it will quit the game.