Well that’s amusing – first time that’s happened!
It’s telling you the problem. The plugin is being called when already inside an output buffer call. How have you done this? Where are you trying to use it ?
A shortcode is a substitution (wp swops the shortcode for whatever the shortcode function returns). Now normal widgets don’t return anything, they just echo directly to the screen at the time they are run, in bits and pieces. Which is fine when it’s in a sidebar BUT With a shortcode, we want it to save the html generated and return it to be inserted into the content where the shortcode is.
So…
What the plugin does is call the widgets, first setting up to catch the output buffer, saving the output, closing the buffer and returning it as the result to replace the shortcode text in the content. Very simple actually. It would be SO easy for widget plugins to also offer a shortcode, but many don’t do it.
What it’s saying in your message is that it’s being called when something else has already started ‘trapping’ the output buffer. Why is this?
