So I'm going to be giving feedback for this specific change right here:

When opening your bank, your tabs will be reset. That means, that opening the bank always opens the default tab, which contains all items.
This is a change some may enjoy, but it has been irritating me beyond belief.
I believe that it should be an option to have this happen.
In most cases, having the tab you opened previously stay the active tab would be beneficial.
This is due to people organizing tabs and having different materials in each tab.

So when it comes to things like herblore (potion making, herb cleaning) and other skills like fletching you know where everything will be when the bank comes back up, so this is less clicking and moving of the mouse.
Less repetitive boring time consuming movement.

However, with this update, you have a lot of un-needed movement just to do something that was 3x easier before this change.
Now, I know people are going to say "pft you're being petty", and try to shoot down my feedback (I see suggestions get shot down far too much in this forum, lol) so I'll say this:

This new change goes fundamently against Fitts' Law which is a law commonly used in design (web design, GUI design, etc...) and is quite important despite it seeming not so important.
(I suggest if you're into design you go and look up Fitts' Law more in depth, it's pretty good information to have.)

My suggestion with this feedback:

Make this an option.
Give people the choice if they want the front tab to always be opened or for it to remember the previous active tab.

Simple fix, gives users of both sides the option to choose which one is more accessible/usable to them.

I believe this happened to resolve an issue some people were having with the scrollbar disappearing, not entirely sure though.

I do agree with you though, it frustrates me beyond belief when I'm trying to skill. I know you can just scroll down your tabs now but it's still frustrating, so much easier to keep a specific tab open depending on what you're doing.