I wanted the panel to stay open on wider screens, e.g. the panel opens when user puts the device in landscape mode.

First I had a JS solution but wanted to solve this issue only with css.

So I added the following css classes to the media query of the responsive panel:

.ui-panel-closed { width: 17em; } .ui-panel-content-wrap.ui-body-c.ui-panel-animate.ui-panel-content-wrap-closed{ margin-left:17em; }

For some more information on my solution, see my post on  Stackoverflow

Since I searched a lot and did not find a solution I just wanted to post it here...