When a sheet is split (and the panes frozen) it is not registered as a change in the sheet and there is no opportunity to save the new state so that it is returned next time the sheet is open. This may be a bug or a feature that has not yet been coded. It is a fairly important feature.
Hi Tony, if you meant freeze pane in XLS file so it's a duplicate to Bug 49742
As indicated by ign_christian, this is a duplicate of Bug 49742.
*** This bug has been marked as a duplicate of bug 49742 ***