Analysis: This seems to depend on the particular chosen Windows desktop "personalization" and some other user-specific configuration we haven't yet identified. On David's Windows 7 machine, the description above is accurate for all but the simplest "Windows Classic" personalization. Phil's Windows 7 machine always shows SOME ornamentation ... SEE SCREENSHOT ... the column header "missing-crosshatch" problem is only with the selected state, i.e. when any of the cells in the slot column are selected. On the selected columns, at least a red frame shows up.

Given the use of the Qt4 model/view architecture, there is no "reasonable" programmatic way of altering this appearance. We provide the "background brush" (pattern and color) for column header cells, and its up to Qt4 to do what it does. Qt4 attempts to reconcile certain provisions with the style theme of the workspace, to make different applications have similar appearance. This necessarily prevents us from having full control of display features.

Solution: In the Vertical Time axis orientations, we will instead crosshatch the actual data cells in columns corresponding to slots on object for which dispatching is disabled.

Analysis: The problem is that it's strangely difficult to cause a QHeaderView to update. There had already been a substantial amount of code introduced to force this update. It's still not working. Note that, in this bug scenario, an update can be manually forced (after clicking Apply in the SCT configuration dialog) by clicking in a different cell in the SCT series data table. I'm still trying to figure out how to do that programmatically! The obvious ways of doing that -- and several non-obvious ways of attempting to do it -- are not working.

The chosen solution was to programmatically, momentarily hide and re-show the SctDialog (only when configuration settings specific to column headers have changed). This is a tad drastic, but this sort of SCT configuration change isn't made very often.