The capture window functionality is different from clicking "Capture window" on the its icon at the task bar than using the keyboard shortcut Alt + Ctrl + Prt Scr button.
I attached a screenshot when clicking on "Capture window" allows the user to place cursor inside the application(in this case ACDSee) and allows to capture a portion of it, in this case is is the dark pane.
If I were to use the keyboard shortcut, it captures the whole window without having the nifty region selection as before so I'd end up with a screenshot of the whole window.
So my question is, is there something in the Preferences that I could do to make them consistent in terms of its functionality wise, I'd prefer to have the first scenario as default as it's more user friendly and I could choose to screen capture either a specific area of the window or I could place my cursor at the top of window which allows me to capture the whole window.
In the settings there is a "Capture" tab, this has an block called "Windows capture", where a radio button defines the capture mode.
You can change this to interactive to get the behavior you are looking for.
This has some disadvantages though, especially on Windows versions before Windows 8, with "Automatically" you will always get a screenshot of the active window via a special way which makes sure the window is captured fully (even when partly outside the screen or behind others) without see-through (the title-bar is transparent and partyl shows what is behind. This is important for when you are making documentation.
Going via the interactive capture, Greenshot currently can only grab the content directly from the screen, producing screenshots as you have uploaded. (I can see something like the Chrome or FireFox browser behind your ACDSee window).
Alternative, without changing the settings, you can press "PrntScreen" and when the region selection comes, press the "space" key to change the mode to what you want.
Cheers Robin for your insights, I very much like the design of "space" key in terms of what I need to achieve without changing its settings.
I wouldn't worry about the see-through on the screencap as long as that's what it appears on the user's screen, I could always turn off the window transparency in the system setting if needed.
You have solved my problem so thanks again.