Strange behaviour in Sage Accounts 50

Just wondering if anyone else has the same problem....

When inputting a customer receipt on Sage 50, on entering the value of the receipt against the invoice line (we do a lot of payments by instalment), the cursor will flip back to the start of the number, and I have to hilight what's already in the box and type again.  It's extremely annoying and means I have to check every single number I put in to make sure that it is correct.

I put up with this for a while, but when inputting a large number of transactions earlier this year, got a bit fed up with the extra work, so phoned Sage.  They said it "wasn't a known problem" and suggested that something on my PC was clashing with the Sage programme, causing the strange behaviour. 

I had no choice but to accept their explanation. 

I use the same programme on my laptop, completely separate from the PC mentioned above.  The same problem's now started happening on my laptop.  Grrr!!! 

Before I go back to Sage, I just wondered if anyone else out there was having a similar problem?

Thanks.