Below are some before and after screenshots of GParted. I simply moved both of the Ubuntu partitions (boot and home) to the left, so that I could resize the home partition (extending it all the way to the right).
The NTFS partition on this drive is not my Windows partition.
Regarding is GParted safe, see GParted FAQ - Is It Safe?
If you move the Linux boot/root partition or Windows boot/C: partition, then you may need to restore the ability to boot.
See GParted Manual - Fixing Operating System Boot Problems and GParted FAQ - Restore Windows Boot.