I'm trying to use Windowbuilder on Eclipse but it always pops up error "Unknown GUI toolkit".
The mainFrame.java is created by the drop down menu below:
I install Windowbuilder from Eclipse MarketPlace.
Looks like everything is installed properly, including SWT Designer.
Here is all my environment:
computer: macbook pro intel i5
Eclipse: 2023-03 (4.27.0)
Java JDK: 17.0.6
I tried un/install Windowbuilder several times but every time end up having the same problem, and I even reinstall java JDK and Eclipse.