The Live Edit Toolbar can be resized by dragging its edge.

If the Live Edit Toolbar is dragged to the edge of the screen to appear closed, attempting to reopen it using the tabs will cause the window to appear to open and then immediately close.
Solution
Hover the mouse cursor on the edge of the Toolbar, at the edge of the browser window

Note:
The mouse cursor will change from an arrow to a Move Cursor when hovered over the edge of the Live Edit Toolbar.
Click and drag the Toolbar window open
Best Practices
Do not drag the Toolbar closed. Instead, either minimize the Toolbar or turn Live Edit off.