Could it be that SystemSettings' toolbar was somewhat detached? Maybe the toolbar is just somewhere in the desktop. Close all applications except SystemSettings and make sure its in focus. If you don't have SystemSettings in focus the detached toolbar will not be visible. If you find it on your desktop, move your cursor to the left of the toolbar until the mouse cursor turns into a cross. Drag the toolbar to the top of the main window until it appears to get docked.
Right-click on the toolbar and select Lock Toolbar Positions to prevent it from littering around.
If it isn't on the desktop, someone else might come along and give another suggestion.
A toolbar-less SystemSettings:
SystemSettings Toolbar undocked:
SystemSettings Toolbar docked: