Extensions don't show in stencyl 3.4(beta 1)

I installed stencyl 3.4(beta 1) and i installed extensions again but after then the default extensions disappeared (like test extensions) and new extensions won't show in extensions blocks even after i enabled them.I uninstalled stencyl 3.4(beta 1) and installed stencyl 3.3.2 and new extensions(like adcolony) appears and works properly as before.is it a bug for stencyl 3.4(beta 1)?

How many extensions have you got enabled ?
Keep trying
I did have the same problem .. I try to have some clues reading the logs
nothing ..
 At the third tentative, my first extension appeared !
now my four extensions seem installed.
caveat : the extensions need to be different ! 
probably a buglet .. boring but nevertheless small

You may need to close/reopen a game after enabling an extension.

But in stencyl 3.3.2 (not 3.4(beta 1)) i didn't need to close/reopen the game.In stencyl 3.3.2 if i enable an extension it appears immediately in extensions section but in 3.4(beta 1) it need to close/reopen the game.and default extensions like (test extension) have disappeared too!I think windows 10 is problem and i will come back to windows 7.

This is fixed now in build 9008.