You probably have the AutoExtend future turned on (ToolsOptions, Edit
tab, 'Extend list formats and formulas).

The following MSKB article explains how Auto Extend works:

XL2000: How Auto Extend List Behavior Works
http://support.microsoft.com/?id=231002


Thief_ wrote:
I've got a workbook which I have added a new worksheet. I copied text from
another worksheet where the data was Filtered from a list of many rows- no
formatting. I pasted the data into the new worksheet, formatted only the
cells with data, using different background colours for each row B6:D20.

I then added some text by typing onto the cells in G10:H20 and the cells
magically aquired the same background colour as the data in B6:D20.
Depending on which row I typed the new text in, the corresponding background
colour in the same row of data in B6:D20 appeared in my new cells.

There's no Conditional Formatting and no macros- so what's going on? It's
not a religious day today, is it?

XL2003



--
Debra Dalgleish
Excel FAQ, Tips & Book List
http://www.contextures.com/tiptech.html