You already answered your own question. Results of a Find In Files search to an edit window are always appended to the tab with name ** Find Results **. If this tab does not exist, it will be created new.

So when you save the content of the find results window to a file, there is no tab with this title anymore and next Find In Files to an edit window will create a new one. It is not possible to have a real file open with that name because * is not allowed and possible in the name of a file or directory.

I played a few minutes with Find In Files with Results to Edit Window, but it always used the existing tab with name ** Find Results **. Even why I edited the content of the results window, deleted the content, moved the tab to a new position in the open file tabs or opened other files, UE used always the same window.

Maybe there is a special situation where the detection of the existing results window fails. If you can find it out, please report it to IDM support.

I have normally not enable the auto-save feature. But just for testing I have enabled it now in UE v13.00a+2. But it ignores the Find Results tab even when Do not auto-save unnamed (new) files is also checked as long as I do not make any manual modification in the find results window which is indicated by an additional * on right side in the file tab.

When I make a manual modification in the find results window and I have checked Do not auto-save unnamed (new) files then the "Save As" dialog opens on next auto-save and I have to enter now a valid name or cancel saving the file. If I press Cancel the Find In Files continues to use the existing tab, although modified by me. If I save it with a valid name, it is normal that the file tab changes to the new name and next time Find In Files creates a new find results tab. So I still can't have multiple tabs with name ** Find Results **.