Open parent cell groups of selected cell

Question

I wrote a small script for a palette, which allows me to highlight a specific cell in a notebook by using SelectionMove[mycell, All, Cell]. The cell is selected as expected, but sometimes this cell is part of a cell group (section, subsection etc.) which is currently closed, so the cell itself is hidden, and SelectionMove does not reveal it. So far, I didn't find a way to open all parent groups of this cell programatically so that this cell will be shown... Is this possible?

Answer 1

You can select parent cell group of currently selected object in notebook nb with SelectionMove[nb, All, CellGroup] and then open it using FrontEndTokenExecute[nb, "SelectionOpenAllGroups"]. To open all groups containing currently selected cell you can use something like this:

FixedPoint[
   (
       SelectionMove[nb, All, CellGroup];
       If[MatchQ[NotebookRead[nb], Cell[CellGroupData[_, Closed], ___]],
           FrontEndTokenExecute[nb, "OpenCloseGroup"]
       ];
       NotebookRead[nb]
   )&
   ,
   Null
]

It will select parent group, open it (if it's closed), return selected cell expression and repeat until returned expression is unchanged (i.e. when there's no parent CellGroup).

Edit

It seems that NotebookLocate automatically opens all groups containing located cell.

So you could just add CellTags to selected cell and then locate it:

SetOptions[NotebookSelection[nb], CellTags -> "MyFavoriteCell"]
SetSelectedNotebook[nb]; NotebookLocate["MyFavoriteCell"]

It should be much faster (and cleaner) than my previous, overcomplicated method.