Pressing the ENTER key on the "start timer" entry from the context menu dismisses the menu but doesn't start the timer. This is happening on version 0.6.2. I checked the ChangeLog for 1.0.2 and saw no mention about a fix, but can't test it since I'm on XFCE version 4.10. Sorry about not specifying the version in bugzilla but it doesn't let me (only shows "unspecified").
Finally tested with 1.0.2. The bug is also present there.
Likewise, selecting a timer with ENTER selects it but doesn't start it when the appropriate preference is enabled.
I'm marking this fixed. It should be OK in the next version of the plugin (not committed to the repo yet).