Filter Processing Indicator

I have certain very complicated filters that I occasionally must apply against a large number of files. It can take up to 30 seconds for Mp3Tag to apply these filters. I have no issue with that, but while the filter is being processed there appears to be no indicator that the processing is taking place. I am often in Notepad trying to determine what is wrong with my filter when the view updates to show me that it worked perfectly.

Am I missing something or does anyone have any suggestions about what I can do?

Additionally it would be nice if there was some indicator that the filter is invalid (unless I am missing that too).

You are right: there is no progress indicator.

An indicator that a filter expression is right or wrong is very difficult as it is not clear if you filter for something that will find a match or will never find a match - and all files are displayed quite rightly.

In the status bar at the bottom of the MP3tag window you see 2 numbers, if you apply a filter: the numbr of actually displayed files and in parenthesis the number of loaded files. This may serve as indicator that some matches have been found.