Unbelievable, PDN devs avoiding the question by steering the thread off topic..this must be the first time it has happened hahaha..
I had this problem a few times these past three years. Today I had this problem again with one PDN tab (just one, new ones and old ones had working selection tools). I am using latest PDN version on latest version of Windows 10 with updated drivers and everything. It's same as what StudioLoading described—it says I used the selection tool in history but it doesn't actually select anything, nor does a selection box show. It is not on 'negate' or anything.