When using the keyboard shortcut CMD+F on my Mac to quickly access the search window and then quickly continuing to enter the search text, the first character is still entered in the code window, not in the search box. I'd say that one has to wait roughly half a second until it is safe to continue typing.

This is especially problematic as the search box may hide the part of the code window where the cursor is located. In case I had highlighted some part of code before, it will get replaced with the first character of the search text and I may find out only later when I complile the code next time. By then, I may still undo until the part in question is restored, but this will also undo all my other changes since then.

System: MacOS High Sierra
Arduino IDE: 1.8.5