User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:35.0) Gecko/20100101 Firefox/35.0 Build ID: 20150122214805 Steps to reproduce: In the old extension development (XUL), panel had a moveTo method which would move the panel while it was showing. The high-level panel API in the add-on SDK does not have a moveTo method, and the only way to move a panel is to first hide it and then show it using new coordinates. This causes flickering even if you do this one after the other if you are doing this multiple times per second. I am developing an add-on which does do this multiple times a second (a panel follows the mouse cursor - so it does not get in the way of it - when it is hovering over a specific element on the page). The solution is to create a moveTo method which works while the panel is showing. I believe it would be best if this takes a 'position' object - the same object as described in Panel options (https://developer.mozilla.org/en-US/Add-ons/SDK/High-Level_APIs/panel#Panel%28options%29), and also used in the show method. I am willing to try to implement this, if someone confirms that this is an appropriate feature.
I think using the show method should do what you want here, even if it is not atm. What do you think Irakli?
Marking this P2, Irakli please change this if you see fit.
(In reply to Erik Vold [:erikvold] (please needinfo? me) from comment #1) > I think using the show method should do what you want here, even if it is > not atm. > > What do you think Irakli? Altering the show method would be an excellent idea (and probably a very minor change), but I think there is a chance it could affect existing add-ons. Perhaps some rely on the *undocumented* behaviour of the panel remaining unaffected if the show function is called while it is already visible. (For reference, this is my add-on which is currently affected by this bug: https://addons.mozilla.org/en-US/firefox/addon/image-gaze/.)
I think this should be handled by a third party module for now, using `getActiveView(panel)` from `sdk/view/core` and modifying the xul element.