@mathmathou, thank you very much 🙂 it didn't work but it's still a neat tool. My scene has 379 geometries in it! 🙂
I've found a workaround, with Meshgrabber active and the tool settings open, you can expand all the objects in the scene tab and scroll down them with the arrow keys keeping an eye on when Meshgrabber shows the morph save button as usable. Once that shows up you know it has Meshgrabber active on it.
After that, one has to switch to a different tool like translate and then back to Meshgrabber or the morph save button will show usable even on objects that doesn't have Meshgrabber deltas active.