Silverlight can display in either full-screen or embedded mode:
Embedded Mode : the application displays within the browser or an out-of-browser app window.
Full-Screen Mode : the application resizes to the current resolution of the monitor and is on top of all other windows.
The Content.IsFullScreen property gets or Sets the Silverlight apps full-screen mode. If you set to true, the Silverlight app displays in full-screen mode, the default is embedded mode. If a web page has several Silverlight plug-ins, only one can be in full-screen mode. Also, the plug-in will not display HTML content in full-screen mode.
When a Silverlight plug-in is set to full-screen it briefly show the message “Press ESC to exit full-screen mode”. This alerts users that the app is in full-screen mode, and give information about how to revert to embedded mode.
A user initiated action is required to enable Full-Screen mode. You can only programmatically switch to full-screen mode only in a user-input event handler otherwise the property setting will be ignored. Limiting the actions that enable full-screen mode ensures that the user is always the initiator of full-screen mode behavior.
When in full-screen mode, keyboard events are disabled. This is a security feature intended to minimize the potential for unintended information to be entered by a user. When in full-screen mode, only the following keys are active:
ENTER, UP ARROW, DOWN ARROW, RIGHT ARROW, LEFT ARROW, PAGE UP, PAGE DOWN, TAB, SPACEBAR, HOME, END
(These restrictions do not apply for apps in Elevated Trust )