Mysterious green markup in fakevim

an long time green markup bug in fakevim mode, this bug can be triggered quite randomly, and I can report one of such procedures to trigger this bug.

reproducible: 100%
tested on 2.5.2 in Gentoo Linux and OS/X(10.7.4)

steps to reproduce:

1, for fakevim options: disable 'Use search dialog'
2, open a file, and move the cursor away from the first line (this bug is also triggered with cursor in the first line)
3, Main menu: Edit->Find/Replace->Find/Replace, or Ctrl-F (or %-F in OS/X) to activate search dialog (not / for vim search)
4, type something in searching input area
5, press Esc once to escape searching and cursor in editing area
6, Type vim command O (to insert a line above)

results:
fakevim starts green markup from file beginning to the current mouse position, and the green markup keeps adjusting to some cursor positions. There's no way to remove the green markup without closing the file. the vim command 'O' seems to be ignored, because there's no newline insertion.

expected results: insert a blank line