The properties window should reflect the properties of the last selected object 
in the {Editor, Explorer}. But this is not the case:

1. Open some Java file in the editor.
2. Select some folder in the Explorer.
3. Click in the editor window -> the properties window displays the properties 
of the Java file. There are two tabs: Properties (selected) and Execution.
4. Click on Execution. For a brief moment, the Execution tab is displayed 
(expected outcome), then the properties window reflects the properties of the 
folder selected in the Explorer.