Been having this same issue for around a year maybe. Now on 2020 v24 and the issue is still there.

I have been having this same issue since version 24. Very frustrating. I have to restart the program to get use of document tabs again.

Please fix

I've been having the same problem. I was hoping the 2020 update would fix it but it hasn't. Same problem as mentioned by others. Multiple files open as tabs and upon opening another file the file that was showing is still shown even though the file just opened does show as a tab and that it is selected. I do run multiple monitors on a MacBook Pro Retina Mid 2012. My Illustrator version is 24.0.

Illustrator is broken!

I have this same problem with multiple tabs, sometimes with only 2 open! It's very frustrating. I have also noticed when this happens, any tabs in my tool windows stop working. For example: Align, Transform, and Path finder can not be switched unless i drag the tab I want into its own window. I can change file tabs if I go into full screen mode and if I wan to switch tabs I have to switch the screen mode again. I'm 23.1.1

Not a feature, but a bug

別のタブを選択しても表示している画面が変わらない時が発生する。
すでに開いているタブを選択しても、表示が変わらない。新しいデータを開いても画面が変わらないトラブルあり。
タブをドラッグして並んでいるところから切り離すと表示される。
再起動すると治る。
以前にも同じ現象があった。

I have been having this same issue in Illustrator and it's unfortunately getting worse even after restarting Illustrator and my computer multiple times. Very frustrating having the workflow interrupted!!
Not sure what to do to fix it-have you found a solution at all?

I have the same problem. It seems to be connected to tabs docked in the main window. If I pull the tab off and make it a separate floating document I can see the correct file. I can even create a new file that docks onto this newly separated floating file and it works ok.

Illustrator 23.0.4 / Macbook Pro Mid 2012 Retina / High Sierra / Multiple monitors (2)

After having a couple of documents open for roughly an hour, I go to open a new document as well. However, after clicking to open this document I am presented with the preview of the document that was already open in the background.

Now when I click on any one of the three documents in illustrator they all show the same preview. You can see in the screen shots, three different documents showing the same preview.

I have to close Illustrator down and reopen it. This happens Multiple times a day and is disrupting my workflow immensely.

I am running version 23.0.3 CC, on a Macbook Pro (Late 2013) - OS Mojave 10.14.3 - 16GB RAM, NVIDIA GT750M, Intel Core i7 2.3 Ghz.

I have the same issue. One file will be open. If I open another file, the will have the correct header file name in the tab, but both tabs will have the first file's contents in it. The second file has to be closed and reopened to display the correct contents.

CC 2019
Illustrator 23.03
MAC OS 10.14.4

Any comments on this?
I have the same problem.
Any suggestions?

iMac (Retina 5K, 27-inch, 2017)
Illustrator is updated to the latest version.

File A is open.
File B is double clicked to open in new tab.
File B info appears in tab header, but File A is displayed as the contents.
File B can be closed and its original contents are preserved.

Illustrator 20.03
Mac OS 10.14.4

has been happening to me non stop! adobe please help!

I have been having the same problem for the last few months. It is driving me crazy and I have to shut everything down and restart. They only way I can work on the next file is by dragging it out of the tabs and have it as its own window. BUT when I do that all my tools don't work unless they are too their own floating 'window'.

Hi Joel,

Thanks for reporting the issue. I tried reproducing this on my computer but couldn't reach to your conclusion. Can you please share the steps and a screen shot if possible with us. Is this happening every time or in some specific scenario. Also please let me know on which OS are you working.

Regards,
Ritika
Illustrator team

I am having a consistent issue that any time I open a second file in illustrator, the view is always on the first file, even if I have the 2nd file selected. I have not found a way to resolve this so I can't copy and paste between files!

Yep same

I have the same issue, honestly ever since I upgraded to Mojave, my adobe has been a MESS!
Are you on Mojave?

Wow I have this issue too could not for the life of me begin to describe the issue though - Thanks for bringing it up - happens to me at least 1-2 times a day - very annoying especially when i've got my rhythm going!

If I have one document open and try to open a new one, Illustrator shows the new filename in the newly opened tab but with the OTHER document's content. This was happening in Photoshop too, and now both programs!