The Windows 7 Taskbar Preview window is too small to have a clear preview of the general contents of some files or programs by default. In fact, you just need to adjust the size of the Windows 7 Taskbar Preview window to resolve this problem.
First click Start/Run, enter regedit in the Run dialog box that pops up, and then press ENTER to open Registry Editor and navigate to the Hkey_current_ Usersoftwaremicrosoftwindowscurrentversionexplorer TaskBand, then in the blank area on the right, select New/dword (32-bit), and follow the prompts to create a new name named " Minthumbsizepx "the DWORD value; Right-click the new DWORD value, select Modify to open the Edit DWORD (32-bit) Value dialog box, and finally check the decimal radio box in the dialog box and enter a specific value in the text box (we recommend you enter 450), click OK button.
After you do this, press the "Ctrl+alt+del" shortcut key, bring up the Windows Task Manager window, and then click the "File/New Task (Run)" command, and then follow the prompts to end and reload the Explorer.exe process.
As a result, when you move the mouse over the taskbar icon, you can clearly preview the contents of the open file or program. Friends with this need may wish to try.