Opening any entry in the log-list using the context-menu's "Edit text" opens a "Text Viewer"-window.
In this window, you can place the blinking text-cursor.
To copy all the text, you can only use the "Select All"-option in the context-menu of the textarea, but not the keyboard-shortcut Ctrl+A.
Selecting any text with the mouse and then hitting Ctrl+C works, though.