Each button has a tooltip that will be displayed when the mouse pointer is hovering over the button itself. Tooltips are used to give further information about the action that the button will perform when clicked.

Please note that some of the buttons can have several tooltips because the button may be used to perform different actions. In other words, the tooltips may change depending on the current editing situation. For example, if the cursor is just blinking somewhere, the tooltip for the "Link" button will be "Insert link" - which means that the button will trigger an action that allows you to create a new link at the current position. However, if you have selected some text, the button will convert the selected text into a link and hence the tooltip will read "Make link". This situation is shown in the screenshot below.

Online Editor: the tooltips may change depending on the current editing situation.