When I make a change on the canvas, say a brush stroke, it takes several seconds for the Overview Docker to reflects the change.
If I open the same file in a new window, it updates almost real-time. So it must be technically possible for Overview Docker to update faster, right?
I noticed that Photoshop has the same problem. But Krita doesn’t need the share Photoshop’s drawbacks 
Yes, technically we could just use a KisCanvas2 object instead of the current widget. It would take a bit of coding, and nobody has done that yet.
I’d like to help… but it seems that Krita development is way harder than I expected. I can’t even build a working executable yet.
On Linux, it’s easy, on Windows it’s no fun, on macOS it’s really hard. I haven’t found a way to build and run Krita without the really long deploy-to-app bundle step, even.
Have you tried building Krita inside a docker environment? I’ve found it pretty easy and comfortable because you automatically get the right environment in the docker container.
Would that work on macOS?
Docker runs on Mac and Windows, yes, and at least with command line applications it seems to work well. Whether there are specific issues with a Krita build or starting a Krita instance, I don’t know.
Yeah but even if I build Krita successfully in a Linux inside a Docker, it would be executable for that specific Linux environment that won’t run on my host (if my host is Windows or macOS), wouldn’t it?
Yes. You need to build on the platform you’re testing it on. But if you build on Linux, it means you have access to Linux and you can also test it there, right?. And then when it’s merged to the official repository, there are nightly builds for all three platforms so you’ll be able to use it.
Also please make sure it’s reported on bugs.kde.org if you don’t plan to implement it right away 
To make sure we don’t forget about it.
Yes, you run Krita inside the Linux docker. Running command line programs inside a docker container works out of the box regardless of the host OS, though running a GUI program is a bit trickier if you aren’t on Linux—you need to install an xserver for the GUI app to draw its GUI. See for example here. Whether this is easier than getting the compilation to run directly on MacOS, I don’t know.
As a last resort, there’s always the possibility to install a Linux inside a virtual machine (e.g. VirtualBox), but that’s more resource-intense and a bit annoying to use. Pretty fail-safe though.
Not sure if VirtualBox would work correctly with tablet drivers… but maybe worth checking
+1 for this. Setting up a clone view window every time is kind of tedious.
Well my tela updates in realtime almost but it suffers a bit with big documents and lack of translation in the panel.
To join in, the low rate interval of the Overview docker is one of the things that really throw me off and was the initial reason why I discovered these forums. For those of us used to taking quick glances to check the overall view of the painting this lag is an issue.
Creating a New Window->New View, hiding dockers and stuff can be tedious. Being able to undock a canvas out of the original Krita window and being able to move it to a secondary monitor would be the best option, but this is another forum topic altogether.
To recognize the positives though, the fact that you can see real time update of your brushstroke on a new view of your canvas is amazing and much better than what photoshop does with multiple instances.
This is a 2020 thread but since this issue is never really solved, I’d like to revive this feature request a bit.
Now there are two ways to have a thumbnail view of the working document.
Overview is still not real time. It’s slightly faster than what I remember, but that’s it.
New View works almost in real time. However it’s very clumsy to use, as it works like a document. If you use subwindow mode, the new view would be hidden behind your working document, and there is no simple way to make it atop. The only way I’ve found is like this:
Man it’s a mess… and if you have more than one documents it’s pretty unusable.
Another issue is that New View can’t be move over the other docked dockers, like Layer, unlike Overview.
Why can’t Overview just be as fast as New View? Or perhaps having an option for how often it’s updated?
The latency of the overvie window is improved in krita 5.3. You can download the krita next nightly and test it yourself, or wait for the 5.3 stable release to use it ! Cheers !
Yeah, it’s better than 5.2, but I think it’s still on the slower side… at least it’s slower than open two views.