I am using Lightroom 5.7.1 with IMAC OS X Yosemite 10.10.4 and have encountered an issue using the radial filter in inverted mode. I am using it on a small object (moon) so the centre dot hides the detail I need to see. Thus, I need to make multiple incremental adjustments and turn the filter on and off in order to the results. In the first instance the tool works fine but after I turn it off and then back on again the adjustments do not do anything. The only way I can get it to work is to use the Reset button and I am back to square one.
It was working but I was having an issue with the Brush not working. Adjustments did nothing. I followed Adobe's advise and deleted the preference file and restarted my computer. That fixed the Brush issue but it is either a coincidence or the fix created a new issue. This is very frustrating. I will very much appreciate advice.
You can hide/ show the pins by pressing the "H" key. I know it doesn't fix the problem completely, but it's an interim solution: you don't have to turn the filter on/ off then. How small is the moon if the dot covers it though? I presume you've tried zooming?