TXC 2 Alpha 3 doesn't behave like the old Version 1, when trying to open several .TEX files. Version 1 used to open all .TEX files as tabs within one TXC instance. TXC 2 Alpha 3 opens every .TEX file in its own instance of TXC.
May be it's not a bug, but a feature. Certainly I'm used to open all .TEX files I'm interested in by marking them within the windows explorer and hitting "Return" expecting that all files are opened in one instance of TXC. Since this doesn't work any more I have to open all files with the "open"-menu or using drag-and-drop, which is in my opinion not so handy as the before mentioned method.