Bizarre mouse click behavior

[Herschel Shepard]

Hello. I've been using iterations of Cakewalk since the mid-90s but have only rarely posted here, though I read stuff frequently. Anyway, I am experiencing some strange mouse behavior, and I wonder if anyone else has had this problem- I couldn't find my specific issue on the forum, so if I missed it I'm sorry to repeat something. Anyway, after I've been working in a project for a while, at some point double-clicking my mouse will no longer allow me to add synths from the plug-in menu, and I can no longer use a double-click to make edits in Melodyne (using ARA). If I close the project and open a brand new one, everything works, but if I go back to the afflicted project, the mouse-clicking problem remains. I've tried messing with the click behavior options to no avail. Any thoughts? Thanks in advance to anyone who might have an idea.