Hello:

Maybe this is a weird thing, but when I try to combine a cell with a set of
previously combined cells, the combined cells are uncombined and then I must to
again click on cells I want to combine. This isn´t important in short spread
sheets, but when the document is quite complex or have a lot of cells combined
this can be very frustrating.

Another thing associated with it is the imposibility to insert a row or column
if that insert is involves a combined cells. I suppose that simply the row or
column is inserted and into the cells combined the combination is bigger. but
now I must to uncombine, insert and again select the "new" set of cells to
combine. This kind of redo makes a lot of my friends to step back to MS Office,
and the productivity for this little things decay. 

The same when you push the delete key, appears a dialog that maybe is better as
a menu option, but in general we want to delete the content of the cell (value
or formula), if I want to delete other things or all, with CTRL+Delete or the
menu item, or something different can improve the usability.

This are suggestions of usability that IMHO the mayority expects when we do this
tasks.

Thanks.