When working with files, you will notice that the files you open will be stacked if they are the same format. For example, when you open two or three Word documents, you will see only one icon in the task, and when you hover over the icon, the file windows will popup.
Windows will combine files together by default, however, you can change the settings to display each item in the taskbar, or vice versa.
Step 1: Right click on the taskbar where there is no icon;
Step 2: In the popup window, select "Taskbar settings" which is at the bottom;
Step 3: In the new window, move down and find "Combine taskbar buttons" section, then
– Select "Always, hide labels" if you want the files with the same format to stack together;
– Select "When taskbar is full" if you want the files to stack together only when the taskbar is full.
– Select "Never" if you want the files with the same format listed individually;