For those who have ever seen screenshots of someone's game and wondered "Oh! How'd they make their windows see through?!", I'm leaving this helpful post here for you:

1. Right click the window you want to modify. Select Properties.
2. The box that comes up will allow you to change various settings.
3. To make the window itself transparent, move the "window Transparency" slider to the right, selecting what percentage of transparency you wish to have. This is especially useful on chat windows, because having a little transparency makes your chat tabs flash more visibly (They light up).
4. You can also make the window border transparent if you wish.
5. Repeat again for any other windows you want to make see-through.

You might also notice other options below. If you want to make it so the window can't be moved or buggered up in any way by accident, click the 'locked' box. If you don't want the border at all, uncheck "show border". If you want it to go away until you mouse over, click "Auto hide on". And if you really need the window title, click "title on".

Hope this helps anyone who has always wondered or who is new to Istaria.