word of warning

[7enz]

becareful not to save your projects with any plugins open...
i have had instances where the reload of the project with more than 2 plugins GUI's tends to cause Reaper to hang in limbo... leaving you to find a older project load.

so be very careful leaving plugin open when saving...
save the project with plugin GUI's closed

[Coachz]

can you post a project or give examples ? Devs love this stuff !

[ChristopherWD]

I had a similar problem in a project and found that loading it with FX offline fixed the problem (it's an option in the open project window I believe).

Another option if you're willing to mess with files is to edit the .rpp project file itself to prevent it from automatically bringing up the problem plugin's GUI on load.

Open the .rpp with any editor and search for "<MASTERFXLIST" (for master track) and "<FXCHAIN" (for each track). Each will have an option just underneath called "SHOW", and you can set it to 0 for the offending tracks.