Within a box with Shift key pressed : if the box is moved, all the connected links will be deleted.

On a link : the link can be moved

On the border of a box : the box can be moved (Click+Slide), a pin may be created (Shift+Click)

On a pin : a link can be created (Click+Slide), the pin can be moved (Shift+Click+Slide)

In the corner of a box : the box can be resized.

Within a box when pressing the Ctrl key. If the bow if moved, the links remain visible (but the motion is slower)

You are ready to edit a text or a value : just click to enter the Edit mode

The Probe mode has been selected in the Calculations menu.

The Probe mode is on and the cursor is placed on a link or a pin (ready to calculate)

The MUSTIG graph is being compiled.

The MUSTIG graph is being saved.

Mustig is calculating - System cursor : depends on your Operating System.