windows 10 - Need to create a swap partition after installation but I already got 4 so GParted won't let me

I'm dual-booting Windows 10 and Manjaro 17 and when I installed the latter I forgot to add a swap partition.

Noticed that and tried to create one from GParted but it is returning the following error when I click on 'New':

It is not possible to create more than 4 primary partitions

If you want more partitions you should first create an extended
partition. Such a partition can contain other partitions. Because an
extended partition is also a primary partition it might be necessary
to remove a primary partition first.

/dev/sda1 is the Windows system reserved partition.

/dev/sda2 is the Windows boot partition.

/dev/sda3 is the other NTFS partition I've been using to store stuff.

/dev/sda4 is the Linux partition.

Already shrinked /dev/sda3 by about 8 GB which I want to use as swap.

Not sure how to proceed.