Hey there, me again ??
Still having the problem after upgrading both your plugin to 1.3.1 and WordPress itself to 3.8.
I have tried in Google Chrome and Firefox (trying to rule out browser issues).
I have tried placing the widget in multiple sidebars, no luck.
I have tried placing your widget AND another widget in the same previously empty sidebar. Upon saving each and refreshing the page, CTMW disappeared from the sidebar and the other one remained.
(This is all on the Appearance > Widgets page)
Have you heard any other reports of this behavior? Or do you have any idea what might cause it?
Thanks!