Use modal Window size for Bootstrap grid (col-*-*)

Hi all, I have a dhtmlx web application and I would like my form to be responsive. They appear in a dhtmlx modal window with a tabbar inside. Each tab has a form.

My problem is that Bootstrap uses the size of the screen (viewport) to be responsive (ex: col-xs-12 means that small screen with use all the space (the 12 columns in the bootstrap grid)). But the modal window is not the viewport/screen so Bootstrap cannot be responsive.

Is there a way to use the size of the dhtmlx modal window as the size of the viewport/screen for Bootstrap?

Thank you very much for your support.

Hi

please check here viewtopic.php?f=5&t=51082