Created an attachment (id=15704) [details]
Test case for formula behavior

OK, I have investigated a little further, and it appears that this bug may kick
in not only when invoking SUM, but whenever (1) you've been working with
multiple sheets, (2) you start editing a formula, and (3) the new style of cell
selector kicks in.

I was editing a cell with a manually entered (F2 key + hand-typed) formula,
something like =B17+E17+... and at some point the cell selector became active. 
Once this happened, it became impossible to enter any formula into the current
sheet: no matter what I did, the formula would appear in the previous sheet
rather than the current one.  The only workaround was to close the document and
re-open it.

This bug makes multi-sheet documents almost unusable.

SVN commit 532606 by nikolaus:

operation	Selection
		Fix multi sheet selections for formulas (internal slang: choices)
		In a few cases the resulting formula was put in a wrong sheet.

Note:	The hiding of the editor for sheets other than the choice's
		starting sheet is intended (see: Canvas::updateEditor()).

BUG: 125941


 M  +2 -14     branches/koffice/1.5/koffice/kspread/kspread_canvas.cc  
 M  +2 -14     trunk/koffice/kspread/kspread_canvas.cc  


--- branches/koffice/1.5/koffice/kspread/kspread_canvas.cc #532605:532606
@@ -3724,20 +3724,8 @@
 {
   Sheet * sheet = activeSheet();
 
-  //Ensure that the choice always has a sheet associated
-  //with it.
-  //
-  //FIXME:  This really doesn't make sense.  The concept of
-  //the 'choice selection' having only one sheet is wrong - because
-  //different parts of the choice selection may be on different
-  //sheets (at least, this doesn't work at the moment, but it should
-  //do).  REVIEW after KSpread 1.5 has been released.
-  //
-  //This is a temporary workaround for now.  It fixes the problem
-  //where the editor would be hidden because the choice's sheet
-  //was not the active sheet.
-  if (!choice()->sheet())
-  	choice()->setSheet( activeSheet() );
+  // Set the starting sheet of the choice.
+  choice()->setSheet( activeSheet() );
 
   if ( !d->cellEditor )
   {
--- trunk/koffice/kspread/kspread_canvas.cc #532605:532606
@@ -3666,20 +3666,8 @@
 {
   Sheet * sheet = activeSheet();
 
-  //Ensure that the choice always has a sheet associated
-  //with it.
-  //
-  //FIXME:  This really doesn't make sense.  The concept of
-  //the 'choice selection' having only one sheet is wrong - because
-  //different parts of the choice selection may be on different
-  //sheets (at least, this doesn't work at the moment, but it should
-  //do).  REVIEW after KSpread 1.5 has been released.
-  //
-  //This is a temporary workaround for now.  It fixes the problem
-  //where the editor would be hidden because the choice's sheet
-  //was not the active sheet.
-  if (!choice()->sheet())
-  	choice()->setSheet( activeSheet() );
+  // Set the starting sheet of the choice.
+  choice()->setSheet( activeSheet() );
 
   if ( !d->cellEditor )
   {