Saga View window scroll is not consistent

[johnsimons]

• Scrolling up and down the Saga View with the scroll option is fine (either with the mouse or with the up/down arrows

• However, the scroll behavior is erratic, and its size changes (see below and compare to the above)

UX impressions

• In general the experience of navigating up/down with the mouse holding down the scroll control is a good enough UX
• Clicking with the mouse on the scroll to bring it to a location does not provide a consistent behavior
• Pressing the up/down (or page up/down) buttons also generates unpredictable results and is not a good UX.

Proposed Fix

• Make the clicking on the the scroll area and pressing the up/down button behave similarly to holding down the mouse button and dragging the scroller to the requested location.

[johnsimons]

Funny I mention this to @distantcam yesterday

[johnsimons]

@distantcam this one is ready for review