I am using Excel as a petty cash ledger. I have been grouping all rows
relating to a particular month so that I can hide previous work whilst I'm
entering information for the current month. On opening Excel today, each
individual group seems to have merged into 1 large group. There are lines
where the '+' signs used to be and empty rows have disappeared. Also, row
numbers are now blue. There was also a '1' & '2' in the top left hand box
above row numbers. If I click on '1' all the grouped information disappears,
apart from the first few entries. What's happening?!

Thanks in advance....