My site is all in one big index.php file

Let me explain
I have a site with 10 different navigation areas, instead of creating 10 different pages, I created one page.
index.php has got all 10 pages within that single file, when a user clicks on a navigation item say "About" it looks for index.php?About and my .htaccess file redirects it to the correct place on my page. This is all working great and I generally use this system because I feel it is more efficient in many respects where there are multiple objects that are used over and over.

Now I am using Online Page Editor and Advanced HTML Editor 3 and gallery and upload and file manager add on too.
I have my editable div within a section of my page, when I click on that it works great and I can edit away, upload pics works great, everything is working, except for save because it says there is no such page due to the .htaccess file.

Is there a parameter I could add to say that the default page is index.php and not to change it to the URL displayed when saving out.

Fixed the issue on my side, quite an easy fix actually but I hope it has no adverse effects later on down the line.

Opened up dmxPageEditor.php

Line 81 - function ReplaceRegionInFile($regionName, $fileName, $newContents, $regionType) {
Line 82 - $contents = "";

Added a new
Line83 - $fileName = '/index.php';

Let the script continue, working.