Same issue here. OS X 10.15.7 Catalina. Latest AD 1.8.6. Document created natively in AD.
I have a line drawing with about 40-50 objects which use Layers for Gradient Overlay (Effects tab in the Designer Persona). I edit these gradients by going to the Effects tab and clicking on the gear icon for Gradient Overlay (all grads exist already - I’m only attempting modifications to them). The gear icon successfully brings up the Layer Effects dialog box. But when I click on the gradients thumbnail (in an attempt to edit the actual values, midpoints, etc, associated with a gradient) - that dialog box doesn’t appear.
To clarify - as per previous comments here - I can typically accomplish the task 5-8 times when first using the app, and then after that it stops working. I typically save and exit AD, then relaunch the app to get that functionality back.
It just happened again, so per support’s advice I created a new object on my canvas and attempted to apply the gradient overlay effect - but as with existing grads, the dialog box remains frozen. Although the object populates with the default gradient, and I can access the Grad Overlay gear icon, I cannot click on grad thumbnail to adjust values, midpoints. So as usual, save and exit AD, and then re-launch app to return functionality.
I wanted to try the advice above on right-clicking on a tab and collapsing to icons - but I right clicked on various tabs and never even got a menu to choose from. I don’t see a gradient tab at all, so not sure if we’re talking about the same app version or platform (I’m on AD desktop 1.8.6 on Mac OS X).
Support - please advise.