Current behavior: 

Currently, when you quit the app, the "Use regexp" toggle in the filter (the checkbox) state is cleared and restored to unselected (not checked—do not use regexp) when the app is restarted.

Requested behavior: 

Make “Use regexp” setting in the Filters to be persistent, so that when you quit the app and restart the regexp filter setting is retained. 

Use case: 

I almost always use regexp filtering.