This happens to me since long, first time I report it here:
Working in a document of ± 40pages. When I change the para style of one or more paragraphes, Indesign can't keep up the screen display with this change and shows the old AND the new situation at the same time on the screen. When moving to a new spread and going back to this page, MOST OF THE TIME it's alright. But very annoying. This has been happening at least since versions 2019.

Using iMac 2015, 24 GB RAM, latest macOS, ID 15.1.1

PS: this bug-page is also annoying (place bug idea ??) , slow, Adobe unworthy (???)

Folks,
Please vote if you have the same issue:

I can't work anymore on more than one packaged doc containing 'Document fonts' folder in each package in InDesign 15.1.1.
Moving frames, selecting text in the frames or switching between two (blank) docs causes an unacceptable huge delay what makes efficient work impossible.

Performance got worse and worse since 15.02 / 15.03 / 15.1 already. Removed ID completely, as well any plug-ins or font management software. Bug occurs on three independent Win10 machines using 15.1.1.
I'm currently working on ID 15.01 which is the only version I can work in still fluently.

Temporary solution:
Renaming or moving one of the 'document fonts' folders enables fluent work on the fly, hiding control panel in ID too. As soon ID accesses fonts in the document fonts folder the issue occurs, no matter what font is used.
Definitely located that the bug is related to this folder only.

Please replicate on your end creating two new packaged files.

Posted the topic in Adobe community forum already:
https://community.adobe.com/t5/indesign/not-able-to-work-on-more-than-one-document-in-indesign-2020-on-windows-10/m-p/11238594?page=1#M192146

Adobe already assisted in a remote support session:
Resetted ID prefs and repaired all Microsoft Visual C++ files 2012-2019 without results.

Thanks
Regards

I've noticed a pattern when clicking on one of my recent file icons... I use two different cloud storage platforms, Dropbox and Sync. Both services are accessed from local folders on the same external hard drive. When trying to open one of the recent DROPBOX files from the Recent start page, I get the dreaded 'Either the file does not exist...' error.

BUT, when I follow the same process with one of the SYNC files, it opens with no issues.

ALSO, I can open files from EITHER service using the File > Open Recent method.

So... could the problem somehow be with the Dropbox integration? Any thoughts, InDesigners? Thanks!

This user is much unhappy that inDesign 2020 no longer provides the zoom view box that appeared in the top menu bar, directly to the right of the help tab. That was a fast, easy way to change the view size of the file in the screen.

I was told by Adobe that this feature was dropped because the screen size view could be achieved by other existing features. Sure... now one must pull down a tab, then go to another command and activate a feature like zoom in and zoom out. And that only shifts the view in or out by one factor, whereas the zoom view box at the top menu bar would let you instantly jump the view in our out by 3 or 4 "sizes."Count me as a most unhappy user who will stay with inDesign 2109.

By the way... inDesign 2020's menu bar is now empty to the right of "help." So what was gained taking this highly useful feature away? And why not give users the option to have that zoom view menu feature in one of the pre-sets like "Essentials Classics"? I will grumble once more about my unhappiness at the loss of this important feature and the hubris of Adobe engineers to drop such a valuable element of this software.

I get the spinning ball every few seconds with InDesign - extremely frustrating! I've tried everything suggested in the community forums.

I'm running a brand new MacBook Pro (16" 2020 with 2.3GHz/Radeon Pro 5500M/32GB/2TB), with Catalina 10.15.6 and InDesign CC 15.1.2. I've used this MBP for LESS THAN A WEEK, and have NO preferences established-it's super clean right now.

So frustratingly slow! Spinning ball every couple of keystrokes. Productivity killed.

I tried everything people have recommended in the community forum including dumping preferences; turning off GPU Performance; changing color preferences to Apple RGB; I have no 3rd party applications running; this is not a complex or large document, and it does not use large photos.

I finally turned off WiFi. That worked immediately. Now I have to turn off WiFi anytime I use InDesign??

This seems like a huge problem that Adobe needs to fix asap - it's ONGOING and NOT new. There is a lot of pent up frustration in users, and Adobe should be careful because people are looking for alternative solutions and will jump ship fast if they find one. I've been a loyal Adobe user, but I can't continue to work like this. It's ridiculous. Please fix this problem asap. Thanks.