I have started noticing this problem a while back. Opening spreadsheets directly from Nautilus sometimes has different behaviors in Unity. This means that sometimes I see the icon pop in the launcher like in the image below:
Other times I have the default LibreOffice icon, even though I have a spreadsheet (LibreOffice Calc) open:
And finally the worst case is when I don't get any icon at all even though I have the spreadsheet open:
In this final case I don't even have the close/minimize/maximize window in the top left corner. I can only close it with ALT+F4.
Any idea why Unity would behave like this?
I don't see a special pattern for this occurrences. Happens apparently random for both .ods and .xls files.