If the editor appears to unexpectedly be missing a number of toolbar rows, eg: one one or two rows of the toolbar is visible, it is most likely that you have added the Toggle Toolbars button to the last of the visible toolbar rows. The Toggle Toolbars button hides all toolbar rows below it until clicked, allowing you to keep the toolbar simple until additional features are required.

Showing and hiding toolbar rows with the Toggle Toolbars button

If it was not your intention to use this feature, remove the button in Editor Profiles -> Features  & Layout.