[Jiaz]

Locking and column model works as expected.
Locking a column just means that the column will not auto change width when you change width of other columns. You're still be able to manually change width via right seperator.
The right column (progress) was width locked and that's why you could not use left seperator to change width, because the locked column could not increase(only via right seperator) and the last column was at max width. I've removed max width with next update so you can free change them all