Please be so kind as to read my full post before responding.
Thank you for your consideration.
My company requires me to develop mostly rather complex PowerApps (or Apps for custom(ized) Dynamics entities with quite a number of fields, and thus DataCards) with numbers of Controls in the hundreds and DataCards in the dozens.
After a certain number of Controls/DataCards, simply adding controls, and/or renaming them (before they have been referenced anywhere) becomes tediously slow, triggering "Please wait" for sometimes minutes.
I am guessing that this is caused by the (otherwise great) feature of automatically adapting formulas to changed control names.
I am just very surprised and annoyed by (as far as I understand and have "programmed") unreferenced controls also causing long delays.
Is anyone aware of this "issue"?
I didn't find any post or idea relating to the slowness of renaming things.
I test on my side, and do not have this issue.
So could you try to clear cache and cookies or change other browsers to test?
Do you test wiht another App?
Is it always very slow?
As I have written in my original post, Studio only slows down significantly for some of the large PowerApps that I am developing.
It isn't always slow.
But it's nowhere near fast in my larger PowerApps.
I have no problems whatsover with smaller PowerApps with maybe 20 DataCards and 100 controls.
I have tried clearing cache, switching browser (tried with Chrome, Firefox, Edge), private mode etc.
This doesn't seem to help consistently for my large PowerApps.
From what I can see in your screenshot/animation, your test App isn't even close to a "large" App where things slow down for me.
Im my slowest App (for development) I have around 70 DataCards in the main Editing Form.
Each DataCard has at least a Label and one kind of Input control, so I am estimating I'll have at least 300 controls (label, text input, combo box) etc as well.
Here's a compressed screen grab (manufactured with GameBar, MovieMaker, and online cropping tool/gif converter) showing how I needed around 4 minutes to add and rename 1 custom DataCard with 1 Label and 1 Button, with most of the time spent waiting.
It also shows one instance of autocompletion messing up and overwriting things it shouldn't.
Could you try adding maybe 60 more custom DataCards with a label and a TextInput for each DataCard to your PowerApp and write me about the performance of adding/removing/renaming DataCards/controls afterwards?
Here's another example, working on the same PowerApp with renaming one (referenced) control takes almost 2 minutes.