<blockquote>Locked by Moderator as a duplicate/re-post. Please continue the discussion in this thread: [/forum/1/738929] Thanks - c</blockquote> == Issue == Firefox is having problems with certain web sites == Description == I discovered some navigation issues with my site relating to different browser behaviors. The Home page (index.html) is actually a Frameset document with two side-by-side windows that call a skinny vertical menu HTML file on the left along with the larger Splash screen HTML file with that "courtyard at night" photo. I have used this design layout frequently as you know. The intended behavior: When you click on a Main Menu button, your selection should fill the Splash Screen window. When a one of the Portfolio categories is selected, that Splash screen should be replaced by a secondary Frameset document that contains two stacked frames inside that Splash screen frame. It appears as: a large photo splash screen on top of a horizontal menu of thumbnail photo images. When a thumbnail photo is clicked, the corresponding large version is displayed in the Splash window above. When that photo is clicked, a jumbo 720 pixel version replaces it in the same splash screen window. The vertical Main Menu should remain accessible throughout. Everything works fine using the Safari browser on the Macintosh where I created this site. However, when using Fire Fox on Mac or PC, that initial index.html Frameset is entirely replaced by the second tier Frameset instead of being inserted into the Splash screen window. The result is that the Home page Main menu vanishes. After all this work, this is an unexpected nightmare. == URL of affected sites == http://www.johncregar.com == User Agent == Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_8; en-us) AppleWebKit/533.16 (KHTML, like Gecko) Version/5.0 Safari/533.16