I'm using eclipse for all my development in Java. But AFAIK vanilla eclipse doesn't have any good support for GUI making. Were I work we use a really good plugin for eclipse called WindowBuilder (made by Instantiations), wich makes eclipse a viable choice. It's a commercial plugin, costs about $200. The really good thing about that plugin is that it generates code that is readable, and it understands your code. So you can use it to draw up your GUI, co back into code and make a few changes by hand and then back into drawing mode and all your handcoded changes is visible :)
Now, this might sound like advertisment, but I assure you I have no affiliation with Instantiations. Just my two cents about eclipse being viable as a GUI tool :)
For Each ctrl As Control In Me.Controls("pnlMainPanel").Controls
If ctrl.GetType Is GetType(System.Windows.Forms.Panel) Then
For Each subCtrl As Control In ctrl.Controls
If subCtrl.GetType Is GetType(System.Windows.Forms.TextBox) Then
If subCtrl.GetType Is ...