New to KDL I am just experimenting with my first project.

I have am trying to put some videos I created into a composite TV screen mask. You know the type I mean. I created a wipe file etc etc.. and the video looks like it is playing in TV.

This works fine for one video. SO if you have this..

Video 1 (standard footage)
< composite masking >
Video 2 (Image of the Television)

However in my case I want the trasistion mask to effect all videos above it.

So if I do this.

Video 1 (standard footage) (yet more video here)
Video 2 (more standard footage that fades in just as Video 1 fades out)
< [ composite masking here ] >
Video 3 (----------------------------------Image of the Television----------------------------------------)

(note. videos 1 and 2 are spread across the timeline, not all paying at same time that might be indicated by my text above)

I want both Video 1 and Video 2 to be affected in the composite TV mask.

When I tried this last night, only Video 2 appeared in the mask. When Video 1 was playing it did not have the mask. It just ran full screen.

How do I do this?

Have you played with the "With Track" option on the Transitions tab ?
It will say "Auto" by default. But you can explicitly tell it which track you are composting with.

http://userbase.kde.org/Kdenlive/Manual/Transitions#Transition_Tab

You might also try the idea described here http://userbase.kde.org/Kdenlive/Manual/Titles#How_to_fade_in_more_than_one_title_sequentially
where you could composite all the tracks against an empty video track - weird idea but it did help in the "How to fade in more than one title sequentially" problem described on that page. And that problem could be similar to yours.