Why does dialog boxes sometimes refuse to change folder?
First, make sure the change folder in dialog box option is enabled. See: Can I change folders in file dialog boxes (Open, Save As, etc.)?
There seems to be an intermittent issue noted in Firefox (and possibly other apps) that interrupt the change folder action initiated by QAP.
Normally, QAP introduces a 100 ms delay at a given step when changing folder in dialog boxes. Making this delay longer may help. In my tests, it increased success rate in Firefox dialog boxes (without resolving the issue completely, unfortunately).
To change this delay, select Options, Various Advanced Options and update the value as shown below. 100 is the default value (in milliseconds). Increase it to 200 (or more) to see how it improves changing folders in Firefox or other apps.
Feel free to use the comment box below to give feedback on this issue.