Solution 1

adoberocks

You just have to assign your FTP  to a local drive letter ( E,F,X,Y etc.).  There are some programs on the internet that can do it.  I used NetDrive .

1. Download NetDrive

2. Map your  server to a local drive

This will not disable  background file activity window fully. You will just get rid off the annoying waiting after CTRL+S .

Solution 2

I found this in one forum:

1. Go to Edit ->Preferences -> Site
2. Find File transfer options
3. Change value of  Select default action after x seconds to 0 . It was 30 before.

activitybar

This should make your saving much faster.