OK, I've just tested it, but as I'm not perfectly sure I understood yoou well, I explain what I did:
You must know that I've two accounts, that I'll call A and B (not too hard to remember this way

)
First, I opened few CW with some contacts using A's CL, and have a look at the different topbars -> all where nice, with this kind of "light effect". Normal.
Second, I opened a few CW with some contacts using A's CL, and then start talking to A with my account B (you follow ?

). Then, I had a look to all my topbars, and they were all OK, with the "light effect".
So perhaps the topbar bug comes from your computer?
What about the resizing, you're right:
After my previous "second", I tested it :
Minimizing it causes no problem, images are well resized.
But maximizing them, and then you have a "whole" --> it's like if you would have a empty tool bar between the "Chat Edit View..." bar and the tabs bar. What's more, some of the opened tabs disappeared

(two out of four, to be exact). But they are always accessible, using the horizontal arrows on the top right of the CW.
Then, just to see, I minimize the window again, and surprize : when the window is small, I can see all tabs again!!
And when, once again, I maximized it, they were three out of four tabs to be displayed... Strange, isnt it?

Now, I've just made another test: you know that you've three ways to min/maximize a window: up/down arrow, right/left arrow, or diagonal arrow.
Well, if I do it in two times: first using up/down, then left/right (or the opposite, no matter), I have no troubles, and get all my tabs.
But if I use the diagonal one, then I lost some tabs...
Don't ask me why

Another thing: when I mini/maximize, the size of the CW where I can write my text become huge (about 3/4 of the CW height), except few tabs, I don't now why some keep the correct size and some others become weird...
These are a lot of things, I don't know wheter or not they're related to your skin or due to aMSN itselfs

If you want me to do some more tests, just ask

PS: Yes, tcl/tk 8.4, my sign is up-to-date
