or is it just me?
I don't have much of a conception of what constitutes a lot of tags for InDesign, but I'm working on something now that has an ever-increasing list and the window seems to have some idiosyncrasies. for instance, the scrollbar and arrows don't work (but a mousewheel does). you can only click on the drop-down list of styles if you click to the far left of it (which threw me completely for a long time). it seems to function fine once you get used to its foibles and i haven't noticed any problems with the actual mapping, i'm just wondering if it's some problem with my install or just something that everyone's used to.
Windows 7, InDesign CC 2015.1
not unless that's an issue that can only affect the Map tags to styles panel.