Mouse Gestures
 
Below, find just a small sampling of mouse gesture commands available once the Mouse Gestures extension is fully installed into your Firefox browser. To get a feel, using your mouse, simply trace the small images displaying in the left of your Fx viewscreen:

RIGHTCLICK at the "dot"...
While holding the RIGHT button down, trace along the line...
When you reach the arrow-head, RELEASE the mouse's right button.

Zoom in/out, etc. on the larger image to the right. Some images zoom quite nicely, others may be over-compressed and will pixelate very quickly.

You will soon discover that the ability to draw a straight line with your mouse is not a crucial issue... If you do encounter problems, inspect your mouse... It may need some cleaning... For that task, you will find some links in the Open Links in Tabs gesture area that may be useful.
 
Zoom In: Over an image, doubles image size... Over text, increases text size.
Zoom Out: Over an image, halves image size... Over text, decreases text size.
Reset Zoom: Will reset all zooming actions performed on a page.
Hide Image: Removes image from page - to display image again, click Firefox's "Reload" button or use the Reset Zoom gesture.
New Window: Over a link or linked image, opens a new window in the foreground... Over a inline image, opens a new window in the foreground containing only the image... Elsewhere, opens a new "blank" window in the foreground.
New Tab: Over a link or linked image, opens a new tab in the background... Elsewhere, opens a new "blank" tab in the foreground.
View Cookies: Quickly check to see what cookies the Website is placing into Firefox when visiting a page.
View Source: Will open the page's "source code" in Firefox's native editor.
Duplicate Window: Will open another Firefox window containing the current page content.
Page Info: Displays a tabbed dialog box with extensive information about the current Webpage, including document type, encoding, size, "forms" architecture, links anchored on page, media found on page, and security information.
Open Links in Tabs: Opens multiple links in tabs in the background... This one doesn't work tracing over the image to the left since it is specifically affiliated with links/anchors found on a page... Practice the gesture over the links below:
      Cleaning a Mouse
      Mouse Cleaning
      Cleaning Your Mouse

As mentioned at the top of this page, these are just a minuscule sampling of the mouse gestures available to you... You can place a button in Firefox's toolbar to quickly pull up the Mouse Gestures "cheat sheet" in the browser's sidebar: RIGHTCLICK in Fx's toolbar > select Customize... from the expanded menu > in the Customize Toolbar widget that opens, find the Mouse Gestures Guide button and drag it to a toolbar > click the Done button when finished to eXit the widget.