I have been developing some custom marker sets, and found that when the planner can't load certain markers from a file (for example, I renamed an image from foo.png to bar.png) two things happend that were bad. I will say, though, that ultimately the software was resilient to my boo boo in that it put some placehoders on the bad markers.
First, I loaded my set that used the now invalid markers, I saw this:
bad_marker.jpg [ 5.81 KiB | Viewed 6114 times ]
The error could be improved in a couple ways. First, it's inaccurate. I'm not missing a "set" in the sense of a tile set, I'm missing a single image from a marker file. Second, it's not telling me which marker set, or which image. Third, don't use title-case for the message...
After clicking OK, I noticed that there were grey squares instead of textured markers - GREAT! This was helpful that it still had the markers, but they were placeholders. As a suggestion, use something like 0xFF0000 as a color. It'll stand out more than the grey. (or, if you're unable to discern red, at least it'll still be grey, right?) But I couldn't seem to select the markers. Clicking on anything seemed to select the entire collection of stuff on the screen. I was able to rotate the image, and rotate it back, and after that I could select the individual pieces. Weird.
It's awesome that the software continues to load, and even better, it marks where the bad markers are. These would just be some tweaks to make it that much better.
Thanks for listening!