The Global Settings screen has the rule "Do Not Allow Users to Change Memo Font" selected under Default Font for Memo Box. However, the BillQuick invoices show up different memo fonts.
There are several reasons that can cause this behavior. Memos might have been copied from somewhere and thus inherited the font display from the source. There is no way to prevent someone from pasting these memos, which are actually recorded as RTF data. However, if you want consistent invoice memos, then they should be entered manually or typed directly in the Memo field.
Another possibility is that the user does not have the default memo font installed on the workstation. In this case, a similar font will be substituted automatically. This can be resolved by installing the correct on your system in the Windows Fonts folder.
