The code below is giving me a strange clipboard. Put the cursor on append_word_to_clipboard and type Ctrl-C. The line gets copied to a new clipboard. Now run the command append_word_to_clipboard and a line gets added to the clipboard but it is prefixed by a light gray right parenthesis character (see attachment) and if you copy the clipboard to a text file the right parenthesis comes too, in column 1. If I turn off "view other control characters" it changes to a small question mark in a box. The status bar shows its value as 0A - linefeed.
Same thing happens if I select a word and type C-S-C append-to-clipboard.
The left-hand window of the clipboard tool-window also goes into some kind of double spacing mode - see attachment.
_command void append_word_to_clipboard() name_info(',')
{
select_whole_word();
append_to_clipboard();
}