Bug 5908: SCT: After switching to a different sheet, SCT scroll position can become out-of-synch
Bug Number: 5908
Release notes (y/n): Yes
For Release Nums: 7.0.5

Gnats 5908: SCT: After switching to a different sheet, SCT scroll position 
can become out-of-synch.

Original Bug Title: 5908: SCT time scroll error.

Some subtle change within Qt, in our upgrade from Qt 4.8.5 to Qt 5.5.1 
(for RiverWare 7.0), in part, caused a scroll-position synchronization 
problem between the SCT series slot table and the associated horizontal 
and vertical scrollbars.  This was initially reported as being in the 
time dimension, but I had been able to reproduce this also in the slot 
dimension.

This was addressed in two ways:

(1) There is now an explicit mechanism to preserve the time-scroll position 
when switching SCT tabs.  This is similar to the mechanism which had been 
implemented on for each Sheet in the slot dimension, except that one 
time-scroll position is common to all sheets.  (The different between 
sheets is strictly the set of slots shown each sheet -- either as rows or 
columns, depending on the axis orientation).  See the treatment of the new 
field, int SctView::_savedTimeScrollPos.

(2) In both the new time-dimension and the old (sheet-specific) slot-
dimension stability mechanisms, when restoring a saved scroll position, 
we first set the scrollbar position to one-pixel off from the saved 
position, and then set it to the saved position.  See the two methods: 
SctView::restoreTimeScrollPos() and SctView::restoreSheetSlotScrollPos 
(const QString& sheetName).

In the testing of these fixes, a different SCT scroll bug, also related 
to SCT Sheets, was found.  A solution to that has also been devised.  
See: Gnats 5911: SCT: When 'Sheets' are used, the 'Go To' function doesn't 
always scroll correctly to the picked slot divider.

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