Hi @JackBibiRoot -
Thanks for the good reply; the OP verified that the fixes currently awaiting merge fixed his freezing on his looping workflow. These fixes contain code that affects the way node rendering is handled in general - so perhaps if your workflow has many nodes and you’re frequently entering and exiting Annotation Edit mode (where the nodes become greyed-ghostly) then this could be the root of your freezing (and the same fix would work for you.)
If you’re feeling adventurous, you could grab the patched workflow editor plugin jar from here:
http://theori.st/take_away/knime/11039/editor.jar (or http://theori.st/take_away/knime/11039/editor.jar.zip if you have supervising software that doesn’t like JAR files to be downloaded).
Then, make sure KNIME is quit; using Explorer, find your knime_3.7.0\plugins\org.knime.workbench.editor_3.7.0.v201811301425 directory. In that directory, rename the existing editor.jar (like editor_jar.bak) so that you still have it around if you want to revert. Then copy the downloaded editor.jar into this directory and run KNIME.