I'm having the exact same problem.
I got an email from customer service, but their suggestions did not work. Have you had any luck? They suggested:
Please do the following within Impulse:
-Click the blue menu button in the upper left
-Click the 'Reset Data' button
-Close impulse and relaunch it. You may notice a long update time, which is normal as it is rebuilding the deleted info.
If this does not resolve the issue, I would suggest uninstalling Impulse, rebooting your PC, and then reinstalling from the latest installer build
Let me know if you found another solution. I'm not having any luck.