cell format changing when when using search and replace.
 

I have a large number of macros that change the formating of cells (fonts, etc).
I'm having trouble replacing text on cells that contain multiple fonts in the same cell. Replacing any any text will changethe formating in the cell. Can anyone help me because on a deadline and cant figure this out.

The problem can be recreated easily by putting a line of text into a cell and making part of the cell BOLD. Now do a search and replace on any part of the cell. The BOLD text will no longer be bold.