In OpenShift Explorer view, expand tree down to cartridge level for an app. Right-click cartridge. The context menu opens away from mouse pointer rather than adjacent to it as it does for other tree items, like connection, domain or app.

I can 100% of time reproduce it by first right-clicking app and then immediately right-clicking (twice) cartridge.

I can't reproduce it by first right-clicking connection or domain and then immediately right-clicking (twice) cartridge.