My Layer, Properties and Rendering toolbar has went missing.
It’s a dockable panel container.
When all of the panels are closed, the container goes away.
Open one panel, like Layer.
If it’s not docked on the side, click and drag it there.
Then right-mouse click on it’s name tab and the menu of the other panels appears. Check the ones you want.
Once they’re open, drag the tabs into the order you want.
For more, search the V6 Help for “Panel options”.