"Found no matches!" text doesn't disappear on the search box unfocus.

[VladiStep]

Describe the bug

When you search something in the code editor, and there are no matches, the "Found no matches!" text stays floating even if you click off the search box, or switching/closing the tab.

Reproducing steps

1. Open any code entry.
2. Search something that's not present in the code (with Ctrl+F).
3. Try to hide the "Found no matches!" text without closing the search box.

Setup Details

1. UndertaleModTool version: commit 40cdca4
2. Operating system: Windows 7 Ultimate SP1 (x64).

[VladiStep]

Actually, that's the issue of AvalonEdit - made the issue there.
But since it's unknown if it will be fixed there, then I'll fix it locally for now.