Additional information is included for older Windows versions.
No worries; the window isn’t gone, and you haven’t lost anything it’s just hidden.
Taskbar grouping might be handy for some, but for most, it’s just an annoyance.

you could stop Windows from doing this by following these steps:
Right-click or tap-and-hold on the taskbar.
In Windows 11 or Windows 10, selectTaskbar settingsin the menu that pops up.
For Windows 8 and older, chooseProperties.

A Window calledSettingswill open.
Windows 8 calls itTaskbar and Navigation properties, and older versions of Windows name itTaskbar and Start Menu Properties.
In Windows 11, selectTaskbar behaviorsat the bottom of the window.

Windows 10 users can skip this step entirely and go straight to Step 4.
The change is saved automatically, so you’re free to skip the final step below.
For Windows 8 and Windows 7, next to theTaskbar buttonsoption, use the drop-down menu to selectNever combine.
See the tip at the bottom of this page for another option you have here.
SelectOKorApplyto confirm the changes.
If prompted, follow any additional on-screen directions.
Or, it’s possible for you to try usingTask Managerto close down and then reopen theexplorer.exeprocess.