Reproducing Steps:
1. open zss.test/display2003.zul
2. select the sheet "cell-border"
3. set border color to red
4. select cells around merged cells, e.g. E31-33 ( B34: D35, or A31-33)
5. select "outline border"
Actual:
outline border are not painted as expected. spreadsheet also paints non-selected cells.
please look at screenshot in attached files.