I created a spreadsheet that uses several different styles. All styles use
the same type and size font but the shading, font color and borders are
different.

The normal format has no borders, no fill/pattern, and the text is black.

Another fill is "User currency format" , it has borders on all sides, a blue
fill/attern and black text.

In some of the cells I have not applied a style to (at least no
intentially), the cell styles are "Normal" before I make an entry, if I enter
text the cell remains formated with the Normal style but If I enter a number
the style changes to "User currency format." Entering text in the cell after
a number has changed the formatting to "User currency format" has no effect
it stays in "User currency format".

I am not using any macros in the spreadsheet.

Does anyone have any idea what causes this behavior?