Q: magic trackpad loses selective functionality in certain programs

Out of the blue, my trackpad has stopped working in certain programs but only for certain functions. For example, when I am replying to an email, I can use the trackpad to click the email open, but I cannot use it to open attachments or to reset the cursor back into the email for editing. I can, however, use it to send the email when completed.

I am guessing the issue is not with the trackpad (since it appears to function) but rather with the software, but I am flummoxed and frustrated. Any thoughts to help?

Thanks in advance.