partitioning - Why I'm seeing a lock besides the partition I'm trying to modify with gparted?

I wanted to create more space for Ubuntu on my hard disk in favor of my Windows partition. I booted the livecd and resized the NTFS partition to 100 GB. Then I wanted to resize my Ubuntu (ext4) partition to fill up the created unallocated space.

A screenshot of my current disk. (With the livecd there's no 'key' icon after sda6)

My first thought was just right click on sda6 → move/resize → done. Unfortunately I cannot resize or move the partition. However I can resize the NTFS partition.

I guess it is because the extended sda4 partition is locked. I couldn't see an unlock possibility though…

So how do I resize the ext4 partition anyway, probably by unlocking the extended partition, but how?

You cannot resize a mounted filesystem, that's why you see a lock icon.

You were doing well, you booted into a Live CD and resized the NTFS partition.

Now you need to enlarge the Extended partition, partitions "inside" that extended partition cannot "escape" outside.

1. Make sure that /dev/sda6 is unmounted. If a lock icon is visible, right click on it and choose for Unmount


2. Make sure that the swap partition /dev/sda5 is unmounted. Right click on it and choose for Swapoff


3. Select /dev/sda4 and choose for Resize. Use the free space on the left side


4. Select /dev/sda6 and resize it on the right side


5. Apply the changes and you're done.