Tracker Supp-Stefan is right, there is this digitizer - option. However it only switches between any tool for the touch-option and only handwriting/pen for the digitizer.
For accurate highlighting, etc., it would be great, if the function would be somehow inverted: With touching, you can only scroll (and zoom?), with a pen, you can do the rest like pen, highlighting, inserting textfields, etc. Saving the tool-states individually would be great!
Thank you for a great program!
Edit: Just found out: Two fingers the same time will enable scrolling/zooming