Manage buttons overlapping with multiple modules in one pane

I am developing a custom skin with custom panes and containers.  I have created a simple 'row' pane in which I intend on placing modules that will be styled by containers.  For example I would place 3 modules in a row and each module would be placed in a container which would effectively place them side by side (via defining their width and adding floats and margins etc).

When in edit mode however, the 'manage' buttons are stacked on top of each other as if there was only one module.

Example of what I currently have:
Image1

Example of what I actually want:
Image2

Any idea what was cause this?  Why are the module manage buttons being placed ove the module instead of at the corner of the containing pane?

Thanks,

Ryan.

Edit: no idea how it ended up in this forum, please move to the relevant area.