Have you came across to a site that only works with Internet Explorer? But you're using either Gecko or Webkit as a default? No Problem. You can change a rendering engine per sites without having your default engine changed.
From Address Bar
You can switch engines for a Web site by clicking the rendering engine selection button shown in the address bar.
- You can click on the rendering engine selection button to change engines (selection rotate among three)
Right-Click on the rendering engine selection button to open up a menu to select your preferred engine
From Engine Icon
- Click the rendering engine icon
- Select your choice of engine
From Right-Click Menu
You can also change a engine from a right-click menu on a tab.