We have implemented an error-log to track when the editor tries to load a broken map object.
Although we have already established a rather robust editor, complex interactions or temporary network hickups can cause the map object to go into a "broken" state.
In February 2019 we've implemented an server-sided tracker to catch such errors automatically and we have also implemented an error message that you can forward to us (don't forget to desribe what you did, so we can reproduce the error). All of this is extremely helpful to catch bugs and make our tools even more robust.
We also help you to resolve those issues, by looking at your map manually and fix it by hand.
But we understand, that you can't always wait until we have fixed your map manually.
So here are some techniques, how you can fix a broken map yourself:
0) Patient Zero of all advice: Don't forget to save!
(Either by the save icon in the top right, or by pressing "S" on your keyboard)
We have several procedures in place that will create semi-autosaves, but nothing is better than making sure that you save once in a while.
1) If WebGL quits on you, don't just close the browser.
2) Try a simple "Refresh" to bring WebGL back to life. Since we utilize the browser's own local database, we have an auto-save of the map you were working on and only your last action will be lost, but the map should come back again.
3) If that didn't help - Make sure you hit "SAVE" first before you exit the editor. This will save the latest state of your map object to the database. (Even a broken one is better than none - because we can't repair what is not saved to our databases).
4) Reset your browser state by visiting https://www.dungeonfog.com/platform/editor/?#/reset.
This will force the map to reload from it's latest browser-save-state and will trigger a repair script that will remove broken entries.
5) You could also create a clone of the map if you want to report the broken map, but want to continue with your map in the meantime. Cloning also removes broken objects and will trigger our repair script.
6) If none of that did help, there is always your Save-History. When you navigate to "MyMaps" and select a map by clicking on the info-area, you will find that the last 10 saves were recorded as a history. So you can always roll back to a previous version.
7) Still need help? Don't forget to visit our Discord server, where you can always find help from the community or our devs: https://discordapp.com/invite/Ewtsk7g
Reporting errors helps us to improve, so don't forget to issue a report if something breaks!
Thanks and happy map making!