Under Settings (Cog Wheel) > Layouts and Fields > Layouts I have Category and Sub Category marked as required.

In Category, I have created a category called other and marked as default. When new tickets are created, they automatically get assigned the category "-None-" I forget if I created that or now.

Under Sub Category I have created a (sub) category called "Other" and have marked it as default.

The problem I am having is that when I select my (main) category, the sub category is defaulting to the first sub category in the list alphabetically and not the "Other" sub category.. 

Eg: I select the category called "Access Request" the sub category is then defaulting to "Database Access" because it is the first in the list alphabetically and not defaulting to "Other".

Eg: I select the category called "Hardware Request" the sub category is then defaulting to "Hard Drive" because it is the first in the list alphabetically and not defaulting to "Other".

Is there a way to fix this?