There are some situations that using "find in files" (Ctrl+Shift+F) can't match anything whereas using "find" dialog box (Ctrl+F) can.

the sample file:
download

the regular expression used to match:


the settings in dialog boxes:






the environment:
win xp sp3; emeditor 10.0.1


ps.
I find it several times that part of the regular expression string appears at the "In folder" text box, when I call the "Find in file" dialog box.