I would like to suggest these features:
1) Ability to save custom canvas size presets and ability to delete existing ones that may not be used frequently.
2) Add math operations to the value editor. Examples: I want a color to have exactly half the current saturation so I just hit a /2 button in the value editor. I want a layer to move up by a certain amount of pixels (already possible but it would still be useful for multiple translations) -> I just add the amount I need without having to calculate it myself.
3) Display the value editor when tapping on Size and Flow, in order to input a specific value.
4) Add resolution, ppi and possibly color profile in the documents view alongside size.
5) Make the whole view more "iOS-like" by renaming files with a tap on their name, by adding drag and drop support and by adding long press menu support for actions like duplicating and deleting.
6) A trash can or a recently deleted folder would be much appreciated in my opinion because it happened a couple times that I had to delete more than a document but also selected (and deleted) one to keep by accident. Not that big of a deal if everything is backed up but I still see it being useful.
7) Being able to export more than one document at a time would also be an appreciated feature.

I agree, it would be cool to have up to 5x5 tiles

One of the latest updates improved view>mirror by using the screen center as pivot (nice one, really) but one thing that should be considered is adding mirrored thumbnails in the layers panel while the view is mirrored. This would be helpful when trying to erase accidental little strokes that make a layer "larger" than it should. To quickly identify those I usually look at the thumbnails but when in mirrored view this "trick" does not work of course. That would also be a bit better-looking since it's consistent with the actual view.

Not sure if it has already been suggested but the gradient in the gradient tool needs to be editable before applying. If it's just 2 colors trial and error is good enough but if you plan to use something precise (4 and up points) that's just unreasonable. The only way to make it work is to apply the gradient to an empty layer and then transform it to match the space it has to fill but this decreases the gradient quality due to interpolation.

There are some old bugs that are not yet fixed along with a couple new ones

Old
- mirror checkmark and deleted history are (as long as you're running ios 13 beta 3, 3 re-release or 4) still issues.
- the app switcher thumbnail is still stretched after rotating the device.
- after hiding or unhiding a layer and zooming out the thumbnail still shows the layer or not, respectively.
- sometimes the color, brush and layers menus are still smaller that they should upon re-entering the app.
- it rarely happens that layers still disappear when hiding/unhiding.
New
- some layers show a different layer's thumbnail while being hidden/unhidden. It's random, might be hard to reproduce.
- the Elastify tool sometimes won't visually show any differences but will still process the changes when applied. The final image will not be different though.

Title says it all. Is that a bug or a feature?

How to set it to local? ICloud is already off in preference>general and there's no setting in system settings>Artstudio Pro

Hi, I applogize in advance for pointing out the same problem I'm facing again and again, but I'm now pretty sure the issue is not (solely) caused by iOS memory management for several reasons: 1) it happens randomly as sometimes the history is deleted even with an empty document and just 1 layer with nothing running in the background, while other times it all works fine with many apps running and a 70/80 layers document. 2) I firmly believe the Ipad Pro 2018 is powerful enough to handle Artstudio Pro as none of these problems existed back in iOS 12 and in Dev. Beta 2. 3) No other app I use presents similar issues, and I'm not just referring to normal apps, I'm talking about other art apps like Affinity Photo and Procreate. 4) It does not always relate to switching apps and thus involving memory; I had it happen just now when i lowered the brightness using the control center. Other times it happens while I'm just drawing or mirroring the canvas (which, correct me if I'm wrong, should both not dramatically increase memory usage) 5) I'm not sure how could iCoud and the history be related, since I'm not even logged in to iCloud and the iCloud preference in Artstudio settings is set to off. I would be very grateful to developers if they could take a look at the issue as I love Artstudio Pro and this issue almost ruins it for me.

Memory management is still broken in iOS 13 beta 4 unfortunately...
Since the app does not reload of anything (and neither do Procreate, Affinity Photo and pretty much any other app) but just displays the "Editing Disabled" popup and wipes the history, couldn't this behaviour be caused by a compatibility issue with the way memory management works in beta 3+ ? Something changed from beta 2, that's for sure, what we still don't know if that's a bug or a change Artstudio Pro needs to be adapted for.