Premiere Pro CC: How to reset control panel group settings
Is 'loose panel group' a free translation of whatever the option is labeled in whatever language you're using Premiere Pro in? Because I can't find an option or button that says exactly this ...

Anyway, you can change workspaces in the menu, click Window → Workspaces and select a workspace preset. If you want the default workspace back, make sure to select the Assembly preset (in Premiere Pro CC). If you want to revert any changes you made to the saved layout, select Reset to Saved Layout from the same submenu or press ALT + SHIFT + 0.