When you switch the Task Manager to this mode, you hide extra buttons, options, or descriptions that are not wanted. Just the main controls and relevant views! This helps you render the manager a clean and elegant look and furthermore, resizing helps easily arrange active windows on the screen, be it horizontally on a big widescreen or squeezing in the good old CRT monitor. Here is a tip where you can re-size your Task Manager & use it as a Desktop Gadget.
Resize & Use Task Manager as Desktop Gadget
Click Ctrl+Shift+Esc to bring up the Task Manager in Windows 7. Click on the Performance tab, to display the CPU Usage & CPU usage History. Just double-click empty space near the border or edge of Windows Task Manager display, most people actually accidentally (rather than by wish) switching their Windows Task Manager to this windowless display mode. You will find, the tabs and the menu bar disappears. Now you will be able to resize the task manager and place it as a desktop gadget
You can similarly do so for the Networking tab.
To restore the Task Manager in its original form, just double-click on the empty space again. Related read: Turn Windows 10 Task Manager into a Widget using Summary View.