Recent mIRC versions doesn't focus text cursor on editbox after mIRC window minimize/maximize. Steps to reproduce:

1. Open mIRC and connect to any server and channel.
2. Click with a mouse below in editbox so that the text cursor is blinking.
3. Use a mouse to minimize and restore mIRC window from taskbar again.
4. Cursor in editbox is *not* blinking and you have to use mouse to type anything.