Bug? CustomView(s) not showing on designer

Hi.
When i open the designer on B4A and go to CustomView this not show the Right Arrow >
and i have tabstrip and customlistview added on my projetct.



if i click on another program, like google chrome, paint etc... and back to b4a it show the right arrow.



how can i fix this?

i m using b4a 7.80

Android
C:\Android\platforms\android-25\android.jar

Java
C:\Program Files\Java\jdk1.8.0_131\bin\javac.exe

thx