Version: 1.1 (using KDE 4.2.0) OS: Linux Installed from: Ubuntu Packages When I have disabled "input field grows with text length" (don't know if that's the right name as I have the German localization) I can press up and down keys to select what I sent to the channel last fine. If I have this feature enabled though, I cannot use the arrow keys anymore to select what I said last.
When the multi-line input box is enabled, you need to use Ctrl+Shift+Up/Down as the arrow keys are reserved for text navigation then.