Pop-Up Level as back/forward link

[Freewind]

Hello,
I have built a foto-gallery with thumnails and a screen-space where the thumbnails should pop-up.
Other than with High-Slide functionality, I would like to have the thumbnails popin`-up at a special area in a special design. This works fine in general.
But for a more ease usage, I would like to add a backward and forward button next to that foto-area. So, people do not necessarily need to click on a thumbnail to make it appearing in the foto-area, but using the buttons it will call a pop-up layer which shows the next foto.
The problem is, when I use as link: "web properties-links-pop up level" and then chossing from the selection the certain targeted pop-up level I have created, it does not work smoothly.
The links work perfectly but the propblem is:
When the user does stick with the mouse over the button-link to click through the slide-show, it does not change the slides and it stucks.
Only once the used moves away from the button and comes back again, the link works properly.
But, the normal behaviour is to stay on the button and click one after the other through the slide-show.
What did I make wrong ? Where is my mistake ?
Or does this only work with a special code ?
(I tried the back/forward button from the tweak, but this does not work with pop-up level, I gues)
Thanks for comments,
regards,
Holger