Thank you so much for pointing this problem out. After checking internally, it appears that this bug was fixed in version 4.3.2 (AP - 16147). This issue happens when workspace gets corrupted. Ideally, like you mentioned, switching the workspace fixes the issue. However, if possible please try the following with your old workspace:
Add a -clearPersistedState command on the top, in your knime.ini file. This file is located in the installation directory of KNIME. For instance C:\Program Files\KNIME is my installation directory.
If above doesn’t work, you can try deleting this file in your workspace directory: .metadata/.plugins/org.eclipse.e4.workbench/workbench.xmi.
Thanks!
The relevant forum questions around this problem are as follows:
