Window Mode Capture
There is two ways to use this feature:
press Shortcut keys for "Capture active window" or
launch Gyazo, press the space key, and click on the window you wish to capture
You can take the same screenshot as if you had captured the active window with the shortcut key.
For Windows
For Mac
A little shadow will appear in the lower right corner.
You can also hold down the Option key and click to squash just the window without shadows