Hi

> I installed the markdown plugin but the preview doesn't work.

Works for me, you _did_ enable it in plugin manager didn't you?

Yes

 
>
> I tried to create a new file and set the file type as markdown from Document menu.I tried to save a file with .md extension, but in either cases I the preview doesn't show anything.

Works for me, everytime I change something in the source the preview
follows.  Does the filetype in the status bar show markdown?


Yes, filetype: Markdown and I see the text highlighted correctly.
 
>
> I tried to click right mouse button on the preview panel and click refresh and  I obtained this error message:
> Error opening file /home/mirko/index.html: No such file or directory

Correct, IIUC webkit is fed the data directly by the plugin, not by
saving a file, but having pretensions of being a browser webkit likely
still has a "home" location like most browsers do, and it tries to
reload that.  If webkit allows that menu to be customised then if
someone wants to send a pull request to remove the useless menu entry
I'm sure it would be welcome.


I haven't the competence to fix it, I can open a documented issue on Github about it

I tried to execute geany from command line to see if some log is produced, but any particular error isn't produced