Open an existing spreadsheet, which has some text in a cell. Double click the cell to switch to edit mode. Click in between the text. Press a key. Notice, that the character does not go to cursor position but is added to line end. I use LOdev 3.5.0 Build ID: 35c8573-95bcc5e-4c1bcb5 on WinXP.
Correction: The character is added at cursor position but the cursor then jumps to line end, so that continues writing is not possible.
is already fixed by noel