… reset the IDE Insight toolbar!
Today, out of a sudden, IDE Insight stopped working in one of my Delphi 10.2.3 Tokyo instances. Other instances (those with different registry keys) were not affected.
After ruling out any third-party tools and Known Packages not common to the other instances, the reason would most likely be found somewhere in the registry.
After a while I had some sort of Dé·jà-vu: Exactly that happened to me quite a while ago and resetting the IDE Insight toolbar fixed it at that time. Unfortunately, I probably had not found the time to take a note of that. This time I do!
To reset the IDE Insight toolbar, select View -> Toolbars -> Customize to open the customize dialog. Under the Toolbars tab select the IDE Insight toolbar, click the Reset button and confirm.