I know that this is an old post, but I think that I figured out why this is happening.  I'm on a 2021 M1 Pro MBP.  Running the latest version (2023.001.20093).  

This has something to do with the adobe cloud connected services.  The simple fix is to click the "home" tab, then select "Starred" instead of "recent".  When I did this, then clicked back to the document I was reviewing, the window resize lag stopped.  Best guess is that it is a sync issue with the cloud, bogging down the software.  

The other solution is to clear your recents or disconnect the cloud services.  

Hope this helps.  

Super iMac, open PDFs on the Apple preview.app or Safari, very smooth, on Acrobat DC painful.
More than a year on this.
It was like this on Mojave, and even a fresh install of the Monterey, same thing...
Totally frustrating to use preview or safari to read PDFs when I pay an app to do it.

Same issue still persists. Is there ever going to be a fix for this?

Update: having many tabs open in a window also gives that window resizing lag. I think the more tabs, the worse the resizing lag.

Here are repro steps with Adobe Acrobat Reader Version 2021.001.20155 (up-to-date as of yesterday). macOS Big Sur 11.2.3.

- Have file tabs enabled in prefs (requires restart)
- Make sure you have many Recent Files (ie they appear in the "Home" tab under "Recent")

1. With Acrobat Reader closed, open a PDF file through your OS (eg double-click it from Finder). If I remember correctly, this window will resize just fine. (If I'm not remembering that correctly, I know some windows do resize just fine. If I remember right the first window that appears when you restore a session resizes just fine.)
2a. Open another PDF file through your OS, then drag it out to create a new window. This new window has resizing lag.
2b. Alternatively, just navigate to the "Home" tab in the original window. Now you have resizing lag.

Optional:
3. Clear your Recent files list in the "Home" tab. Now you've solved your resizing lag.

I'm running the latest Acrobat version on Windows 10 x64 and am experiencing that very issue, too.

Running Adobe Acrobat Pro DC 2019.021.20061

Same problem resizing window. Often takes multiple attempts at grabbing the edge of the screen before it will actually start to resize and when it finally does start to move it lags severely. Very frustrating to use.

Going to look for a previous (pre DC) version to install, since nothing is being done about this issue.

Please don't respond by apologizing about the frustration. Just fix the problem or at least let us know someone is working on it.

I have Acrobat Standard DC 2019.012.20036 and resizing the windows is extremely laggy. As said below, it has been over a year since the issue was reported. Marking a request as "NEED INFO" and then doing nothing is the easy approach. Please install your own product on a Windows 10 computer and see how windows resize works.

Almost a year from original reports and issue is still not fixed in ver. 2019.012.20035

I'm running Version 2019.010.20098 and I'm having the same issue. Resizing the window is a very basic function and the lag is very annoying. Please let me know when a fix has been implemented. Thanks.

I am having the same issue with the windows resize handles. Scrolling a pdf is fast but for some reason when I change the windows size using any of the window handles there is extreme levels of lag. Something is programmed wrong.

I have the same issue. It's Adobe. I suspect inelegance in the way the way they change zoom/resolution. When I move the DC window between displays having different resolutions, the DC window literally stops halfway between the move, then studders its way into the new display. If I move the DC window between displays of the same resolution, it passes without incident.