I am working on a GUI system - and therefore make extensive use of these commands.
To chek if the code is ok, I used to male a log file and copy paste it into a wdl panel.

But there I noticed that there is line length limit-
Does this affect the dll generated line too? Is there any limitation here?
One of my GUI elements is a directory system, so there may be hundred of buttons in line.

Yes, I believe there is a line length limit, but you can overcome this by splitting your definition over several lines.