Thanks for the information. It's strange that it is working normally for some people, but for me almost unusable. If I can be of any assistance I'll be glad to provide any help I can give (testing, more information, etc). For know I'll just use the incomplete gdtf library I managed to create, but leave it on WIP. At least I can control the fixture. Once the issues are sorted out I'll update it with the rest of the information.

Tried another browser (original was Chrome, new was Edge), didn't make much of a difference either. I did find out however that if I just press the upload button directly, instad of going through the tabs that it will upload the file including the changes. However when I refresh the page all new info is still gone, and I have to upload the new gdtf file to continue.

Sorry for the late reply. I do use adblocking software, and turned it off without much result. I also tried this process on another computer with the same experience. I tried to narrow down the problem by changing only a few little things at a time and then refreshing the page and see if the changes saved. It is a bit fickle, but it looks like I have the most problems when I try to edit the channel sets of the first gobo wheel. I can add the empty sets, but as soon as I try to set the wheel slot, or change the dmx information it won't save that and anything I do afterwards. I did manage to create a "working" gdtf file by only filling in the dmx channels and not creating any channel sets, but would still like to finish the file properly.

I am trying to create a gdtf file for the JB Lighting P12 Spot (because for some reason the MA3 does not load the MA2 library). Yesterday I tried the first time, it took 2 hours and at the end it wouldn't upload. When I reloaded the page all my work was gone...The second time I started again from scratch, and halfway through I reloaded the page just to check the session was saving and everything was gone again. Today I was trying for the third time, and for some reason after 10 minutes or so my session does not sync anymore and any work I do after that is lost! I'm slowly adding information, but I have to reload the page very often just to check the information is saving, this is not inteded behavior right? Am I doing something wrong or is the builder just buggy?