How to resize help box?

[Mithrill]

Hey everybody,

 

I'm complete noob to Spriter and today I ran into a first problem. I pop up help box to search some help (naturally ^^). Then, I wanted to move help box to side. Instead, it was resized and placed into the editor. That was not what I intended to do. I pop out the help box and now it's size is stuck.  

 

My question is: how I can resize help box? I tried to grab each of the sides and drag but no dice. Only part can I can move is that centre line which divides index and content of help file. If I close and reopen help box, size will stay the same.

 

I know that solution will be so simple but somehow I can't figure it out :/ I'm running Spriter Pro release 10 under Mac OS X 10.9.5. 

 

-M-