Regarding the "Modal region" region template in theme 25, version 4.2.0+
I have an example app here http://apex.oracle.com/pls/apex/f?p=72427:1
I'm trying to imitate the same layout I have on the home page within the modal, ie - the two subregions should be side-by-side,
I've defined by the grid layout using 'Start New Row' = No for the second region.
I've experimented with various style settings but with no success. I would imagine the solution will be concise, but I need help.
(note I've resized the modal subregions to 200px in region attributes)
User : otn
Password : apex
I had a look at your example and the issue appears to be related to the auto column span. Regardless of if the sub regions have content and styling set the autosize functionality is not functioning correctly. I'm not sure if this is suitable for you but I removed the styling from sub reason 1 and instead set a column span of 3 on both sub a and sub b. By using a set column span this appears to resolve the issue.
Hope this helps.
I'm still getting used to the grid layout and visualising what's going on. I saw a great presentation recently by mark.lancaster that helped explain the RWD layout.
Would be nifty if APEX embedded some of the debugging tools I saw.