Clicking with button 1 on the "knob" followed by button 1 movement will adjust the zoomfactor.

Clicking with button 1 on the shown percentage allows editing the given zoomfactor (in percent) directly with the keyboard. Double clicking on the value shown selects the whole entry for easy overtyping.

Clicking with button 1 below or above the knob increases or decreass the zoom factor with 1%. Use this function to easily fine-adjust the percentage.

Clicking with button 1 or button 2 on the Zoom tool, or anywhere outside the slider panel closes the panel.

The keyboard can be used to operate the Zoom Slider as follows: When the Zoom icon in the toolbar has the focus (indicated by the thin blue box around it), then pressing the spacebar opens the zoon slider panel. Use the arrow keys to increase and decrease the percentage 1 by 1. Use Shift-Tab to set the focus to the percentage box, where you can edit the given value directly. Pressing Enter activates the changed value. When the "knob" has the focus, pressing PageUp/PageDown increases/decreases the percentage by some amount. Pressing Home sets the percentage to 300%, and End sets it to 25%.