org.eclipse.swt.SWTException: “Widget is disposed” when trying to open AndroidManifest.xml

Restarting the Eclipse IDE solved the problem.

Eclipse - Kepler / Luna / Mars

for me I went to

...\.metadata.plugins\org.eclipse.e4.workbench // folder locaiton.

and deleted all the content of

workbench.xmi

and restarted the application.

Worked for me hopefully will work for you.

Note: Good to take back up before making changes.

Start Eclipse via command prompt by entering command: eclipse -clean solved my problem.