Xojo issued a dot release today for Xojo 2015 R4. Release 4.1 fixes some relatively important bugs and you should update to it. Even though this was, obviously, released in 2016 any licenses that were valid for 2015 R4 can still update to this release.
If you are using any plugins that are doing drawing via the graphics method you may have noticed that they don’t draw in the proper location in the IDE (but still work in compiled apps). I noticed this with several Einhugur plugins and those appears to work properly in the IDE now.
A number of new Xojo framework items have been fixed. Xojo.Core.Date and Xojo.Core.TimeZone no longer leak memory. Xojo.IO.FolderItem iteration now works on Mac OS X (caused a crash before).
In Windows, the Listbox no longer leaks memory. In Linux, attempting to send anything to the graphics object from a Printer no longer crashes.
Complete release notes at http://developer.xojo.com/2015r41-release-notes