I do not know in NX4, Can tell you the procedure to change the background colors in NX2, Same may be applicable for NX4.
->Check which is your default file from ugii_env.dat,it may be ug_metric.def or ug_english.def.
->Make changes in these file in the required area and will be applicable for all new files you create
You DO NOT set the background colors the same way in NX2 as you do in NX3 or NX4. NX2 relies on the old customer defaults where you edit ug_english.def or ug_metric.def to set the defaults. Starting with NX3, the customer defaults have been integrated into an NX session, so you can set the defaults within an NX session. However, any changes made during an NX session do not take effect until the next time NX is started.
Now, in order to change the background color in NX3 (I don't have NX4 installed, but I assume it hasn't changed), you need to start NX, then when you're at the No Part State, choose File -> Utilities -> Customer Defaults to bring up the Customer Defaults dialog. You will need to decide how you wish to admin your defaults. You can set them at a site, group or user level. Once all that is done, click on Visualization on the left side of the dialog and you should now see a Background tab on the upper right side (near the middle). Click the Background tab and there you are. Set your background however you wish and then OK out to save the defaults (if you have permission to change them).
Then you have got something not setup correctly. Make sure you have read/write access to ALL directories that your customer defaults file(s) reside in. I believe the defaults files are now .dpv files and there's one each for USER, SITE, and GROUP. You decide which level you wish to implement, then make sure there's proper permissions and that the defaults aren't locked.
This is all covered quite well in the documentation.
You didn't specify whether or not you were wanting to change the background color of an EXISTING file or all NEW files (when you click File -> New). Yes, it does make a difference. The customer defaults route ONLY changes the background for NEW files. If you wish to change the background of an EXISTING part file, you need to bring up Visualization Preferences.
To do this, open your part file and select Preferences -> Visualization and this will bring up the Visualization Preferences dialog. Click on the Color Palette tab and at the bottom there are 2 buttons, Edit Background and Edit Color. Select Edit Background and change the colors as you wish then SAVE the part to save the changes you've made. Keep in mind THIS DOES NOT CHANGE ANYTHING FOR NEW PART FILES, IT ONLY CHANGES THE SINGLE PART FILE IN WHICH YOU MADE THE CHANGE. If you wish for all new parts to have this background color, then you MUST do it from the customer defaults menu as I outlined before.
I'VE DONE ALL THAT- - IT DOESN'T CHANGE WHEN I OPEN A NEW PART FILE. I DID CALL EDS SUPPORT TODAY AND THEY HAD SAME PROBLEM. THEY ARE SUPPOSE TO GET BACK WITH ME TOMARROW
Are you clicking on plain under Shaded views and Wireframe Views? Also, what level are you on? Site, group or user? And you have access to change site and group?
I guess that means the colors you had initially defined had been changed, since you had to redefine the colors using a CDF file. Would have been helpful to know this up front.