Do not start a tool immediately in the constructor. This will lead to race conditions.
Also we try to connect signals to tools AFTER they started doing their job. This will not work for tasks that close immediately, e.g. "Scan for new items" on a very small collection. In this case the signal becomes connected AFTER the tool is done, therefore never executing the assigned slot. There are still some race conditions left, I need to check them, but for now the main issue in this bug report should be solved. CCBUG: 297614