I recently migrated custom WebPart template solution (wsp), which has custom list definition, from SP2010 to SP2013 using Visual Studio 2013. Set the Assembly Version to 15 and compiled over .Net Framework 4.5. The deploymnet was successful. But there are 2 problems:
1. When I created site using the custom template that was just deployed, the page displays cluttered icons, attached screen shots. Also when trying to add permission to the site, a whole bunch of colorful cluttered icons appear on the site's Permissions page.
2. The other issue is, some of the CSS, specifically the ms-WPxxxxxxxx (like WPTitle, WPHeader etc) are being inherited, probably from corev4.css. That’s what View Source shows. The custom CSS is defined in the main page (CustomDefault.aspx) with “!important” tag, but that didn’t seem to be of any use.
The same solution was working perfect on SP2010.
Suspect mostly (1) is related to (2), I may be wrong.
To resolve (1), as advised by SP folks from MSDN Community forum, I changed the default master page to Oslo.master ==> that cleared the cluttering icons, but CSS and Javascripts werent working. So I had to revert. I also tried changing the "../_layouts/.." to "../_layouts/15/..", that didnt make any difference.
Any help will be appreciated.