Select a java file in the explorer, and then the execution tab in the universal 
properties sheet. Click the "..." button for the Executor property.

The Executor property editor comes up. Any node that you pick inside of this 
modal dialog box causes the the universal property sheet to change selection. 
This makes no sense. As far as I know, I am editing the executor for the 
selected java file, and now it's properties have disappeared! I find it quite 
disconterting.

There is no need for the universal properties sheet to work this way. For one, 
thing, you can't use it anyway, because the executor dialog box that comes up 
is modal. Also, it is very confusing, because as I change the selection from 
one executor to another, I am actually affecting the executor selected for my 
Java class, but the feedback is gone.