I cannot use a built-in spellchecker. Whats going on?
Check if any of the dictionaries are selected. You can do it for all the projects (menu: Configuration/Options, section: Spellchecking/Dictionaries) or for the current project only (menu: Configuration/Project options, section: Dictionaries). When the dictionaries are selected, the spellchecker is enabled. Incorrect words will be underlined. When you right-click on an incorrect word you will see the list of suggestions. You can also use the hot key Ctrl+D.