Refactor scrollbar drawing and scaling: "MovableInterface" etc. are a single item, no need to wrap their data tuples in a list then use a for-loop to extract those tuples; reduce duplication. TODO: convert scrollbar data into a proper class.
Performance tweak to drawing code; remove unreachable code block (DataCanvas.isAppend is never set to True); more descriptive error message when attempting to start a splice with non-topmost core
Init DataCanvas.selectScroll to 0: otherwise dragging core from core area to splice area fails on the first attempt if you haven't clicked elsewhere (scrollSelected is set to 0 on mouse up)
Ensure Display window GUI is laid out properly when displayed
Remove (nearly) all *-style imports, remove underscore from XML_Handler class name
Unused item cleanup: "dir" component from scrollbars' DrawData, OnScroll method, "Flash" DrawData item
Remove vast swaths of unused code bound to legacy(?) menu items