To install Click Modifiers:
for Firefox v10+
In Firefox either
Firefox will open a dialog box asking you to confirm that you want to install the add-on.
You may need to wait a few seconds for Firefox to enable the Install Now button.
Click on the Install Now button once it has been enabled.
Changing Click Modifiers' Settings
Click Modifiers' settings are adjusted from Firefox's Add-ons Manager tab. To access Click
From the menubar, click on the Tools menu, and then click Add-ons. The Add-ons Manager
tab will open.
Click the Extensions panel.
Click the Preferences button next to the Click Modifiers entry.
Changing Actions for Modifier Keys and the Middle Mouse
The actions for modifier keys and the middle mouse button are set from Click Modifiers' settings
screen. By default each modifier key and the middle mouse button uses Firefox' default actions.
The actions for each modifier key and the middle mouse button can be changed by selecting the
desired action from the adjacent drop down menu. Note that it may not be possible to change the
action for all modifier keys on each platofrm since they may already be used for system or
Available Actions for Modifier Keys and the Middle Mouse
The actions for modifier keys and the middle mouse button can be set to one of the following
Uses default action
Opens link in current window/tab
Opens link in new window
Opens link in new tab
Opens link in new background tab
Secondary Action for Shift Key
In addition to performing the action that is configured for the shift key, the shift key also
performs a secondary function of temporarily toggling whether tabs open in the foreground or
background when used with another modifier key or middle mouse button which has been configured
to open links in a new tab or background tab.