For a project at work we use Bootstrap Modal windows in JavaScript. We would like to make some of the windows movable, but we are running into performance issues with JQuery.
This does not exactly answer your questions, but you may try to disable the *-transition properties or decreasing the time value from the specified 0.3s. This is defined in .modal.fade. But this will mess with the initial pop-up animation too. If this is not acceptable, you may use the start event of the draggable widget to apply the new style.