Press and hold Ctrl while pressing 0 to reset the Firefox zoom.

If the problem is not solved, then.

Disable Flash hardware acceleration

1.Make sure you are using the latest version of Flash. To check your version, see Adobe's About page.

2.Navigate to a page that shows a video that you can't view in full screen.

3.Right-click on the video player and click Settings in the context menu. The Adobe Flash Player Settings screen will open.

4.Click on the icon at the bottom-left of the Adobe Flash Player Settings window to open the Display panel.

5.Remove the check mark from Enable hardware acceleration.

6.Click Close to close the Adobe Flash Player Settings Window.

Hmm.. I'm about Firefox Android version

Try this addon,it will make Firefox for Android use the full screen.

[https://addons.mozilla.org/En-us/mobi.../full-screen-252573/]

Doesn't help :(

Press and hold Ctrl while pressing 0 to reset the Firefox zoom.

If the problem is not solved, then.

Disable Flash hardware acceleration

1.Make sure you are using the latest version of Flash. To check your version, see Adobe's About page.

2.Navigate to a page that shows a video that you can't view in full screen.

3.Right-click on the video player and click Settings in the context menu. The Adobe Flash Player Settings screen will open.

4.Click on the icon at the bottom-left of the Adobe Flash Player Settings window to open the Display panel.

5.Remove the check mark from Enable hardware acceleration.

6.Click Close to close the Adobe Flash Player Settings Window.

Many site issues can be caused by corrupt cookies or cache. In order to try to fix these problems, the first step is to clear both cookies and the cache. The Firefox cache temporarily stores images, scripts, and other parts of websites while you are browsing. Note: This will temporarily log you out of all sites you're logged in to. To clear cache and cookies, do the following:

1. Tap the menu icon located at the top right corner. This is the icon with 3 bars. On older Android devices you'll have to press the hardware menu key and then tap More.
2. Tap Settings.
3. After that, you will be taken to the settings screen. In the settings screen, look under the section Privacy & Security and select Clear private data.
4. You will then be taken to a list of what can be cleared. Select the following 2 for deletion:

• Cookies & active logins
• Cache

    After those have been selected, tap the Clear data button to actually clear the cache and cookies.

Just look There's no even button for fullscreen mode http://s2.postimg.org/x9rnv6art/tmp_Screenshots_2013_10_28_08_24_41_247832640.png http://s7.postimg.org/lq777v2wr/tmp_Screenshots_2013_10_28_18_26_59_1254513932.png