Window popup only works on second click

[Rosinger]

Hi all,

I have implemented a simple window popup with window.open(), which
displays an image in it. I refer to it in a <a
href=javascript:imagePopup(image_url) ...

The imagePopup is the function that opens the window, and displays the
image.

For some reason, I need to click _twice_ on the link in order for that
window to popup with the image in it. The first click on the link
seems to be "swallowed" and does not have anu effect.

Any ideas why this happens?

Cheers,

Dave