I have two sheets which I wish to merge. I select all cells in the first one by clicking on the box in the upper-left-hand corner, between the row labels and column labels. I hit Ctrl-c. Then I select a cell in the second sheet and hit Ctrl-v. I get the error: "There is not enough space on the sheet to insert here." This does not make sense; there are only a few rows and columns in the first sheet. If I explicitly select the rows and columns I need (all of those that actually have data, not including the seemingly infinite number of empty cells) by dragging from one corner of the data to its diagonal opposite, I can cut-and-paste without any problem. I think this operation should just work without any questions, perhaps unless there's a question about whether or not the "empty" cells at the fringes of the copied should erase data in the one being pasted into. A more helpful error message would also be an improvement. This is with openoffice.org-calc-2.0.4-5.5.17.
See: http://qa.openoffice.org/issues/show_bug.cgi?id=74545 basically the empty rows and columns do matter, excel does this as well. You could raise a suggestion upstream to select only the cells with content in them when clicking the currently "select all" top left corner button. Or some other way of handling the paste, but for the moment this is how it works by design.
Well, my point is that the behavior is not very user-friendly, whether or not it was intentional or is just as unfriendly as other applications. In any case, I have taken your suggestion and opened a new request at http://qa.openoffice.org/issues/show_bug.cgi?id=75880