Premiere Rush won't trim videos anymore

When I click on either the left or right ends of the video to then shorten that video (from the start inwards or from the end backwards), the blue cursor thing (bad description) immediately snaps back to the start or end.  At that point I cannot drag the start and ends points of the video to trim it.  This process used to work (somewhat, it was hit or miss), but now it never works.   What is the solution?