Default Virtual keyboard lag and reader app writing on the surface pro

Hi there!!

I have a surface PRO and I use it to take notes on top of pdf with onenote. I think that is a very great machine with 360 capabilities. Anyway I have 2 problems with it:

1) I have lag on virtual keaybord, mostly when the keyboard shows up and I instalty start writing, letters appears some seconds after, then it works fine.

2) the reader app works very bad with the pen for handwriting. Who own a surface pro know what I'm talking about. While writing if you keep the pen on the screen to write a long word the app start messing and square letteres comes out of it.

ANyway has some fix or solution for these 2 things?