Tk Source Code

On OS X (and apparently Windows as well), the Tk clipboard is 'lazy' - it doesn't appear to be copied to the main system clipboard until asked.  If the Tk app is quit before this happens, the copied text is lost forever.

Obviously this has its uses (say, copying large chunks of video), but makes other workflows very frustrating.  I use gitk for browsing my git commits - typical workflow would be to fire up gitk from the terminal, find the commit I'm interested, copy the relevant SHA1 id, quit gitk, and paste that id to the terminal.  Tk's current pasteboard implementation prevents this.

Are there any workarounds?

On Windows this is really not the case, just try it:

package require Tk
pack [text .t]
.t insert end "abcdef"
.t tag add sel 1.2 1.4
event generate .t <<Copy>>
# quit wish and paste somewhere: "cd" is correctly inserted on Windows.

On Linux this depends on the presence of an adequate clipboard manager. We had a discussion about this on comp.lang.tcl very recently about this point and I think what Rich and Brian stated there is very clear. There is no bug in Tk here.

On macOS, I have just checked on Mojave: it's not (or no longer) the case either (same test script). Perhaps there is a clipboard manager on the machine I tried this but in any case I don't see a bug.