Hi Cameron
Hitting apply in Panel Builder will always trigger a rebuild of the custom panel. If no changes are made, hitting "close" instead of "apply" will dismiss the editor without triggering a rebuild.
I think the trick would be to find a way for you to make your panel more configurable outside of edit mode to make sure you don't need to edit your panel in the middle of a show. Failing that, finding a way to make sure the state of your panel is stored inside of parameters or an external file and handling restoring the state "onload" via script would make it so that you can make modifications as necessary.
If you are already using parameters, make sure you don't have the "Do not save changes made to parameter value" checkbox checked as that will cause them to restored to their original value whenever the panel is rebuilt.
If you have any questions about these approaches, please follow-up and we can try to assist further.
Cheers
James
#DashBoard