Loaded file settings affect textbox code

[peterennis]

Fill is carried over from loaded script into the textbox code.

Related: https://github.com/spakin/SimpInkScr/issues/20

[spakin]

This behavior is as intended. The idea is that one can encode a bunch of common function definitions and parameter settings in a Python file then write a few lines of code in the Python code box that relies on those definitions and settings.