Browser Compatibility (Mozilla)
 

Viewing your homepage http://www.xolox.nl/ in Mozilla 0.9.3 gives the user undesired results. It is impossible to view anything except the home page due to the menu not operating properly. Some research would have given you the script http://www.simplythebest.net/info/dhtmlscript79.html , from the same site you got the menu script you are currently using. The script listed here is cross-browser. There are other scripts available on that site, that's just the first one I saw. This is not a Mozilla bug.

The table on http://www.xolox.nl/text/welcome.html also appears incorrectly, but looking at your code I am unable to determine whether this is a coding error or a bug in Mozilla.

A quick test also revealed that your center frame is too wide, being unable to be viewed on a screen set to 640x480, regardless of browser.

Nitpick: the black used in the background of your images is not the same as the black used by either IE 5 or Mozilla for the background.

issues with browser integration
 

I understand your plight with browser integrations. However, since IE has made newer browsers, browser codes from 6 are not compatible with v5.5 and they aren't compatible with v5, etc.... There is no more real browser integration codes. There was a belief before that XML coding might help and that it can give the right hues of colors. I just saw a conference with regards to this and it was mentioned they cannot really tell the difference from candy red to cherry red.
Just like photoshop or a printer, there are certain colors used (mainly 6) to try and mix the right tones/hues to portray them as closely as possible. This ofcourse with the new XML coding does not always read in accordance with all browsers.
Hopefully future codes will be more cross platform based but, as everyone knows, MS & Modzilla type browser companies are like children fighting for the only chocolate chip cookie. Not willing to share/split it.

Doesn't work with Opera 5.12 either, nor Lynx or a host of other browsers. Basically the Xolox pages works in IE only. Shame on you.

Dear people,

We have prioritized the changes needed.
Converting the web page isn't high on that list...

Sorry, but our time is limited ...
:)

Pasman
XoloX-team