Ever used firebug or google chrome inspector? Is there any similar way to inspect elements in the desktop environment to get their "element name" or "class" or "id"?
Actually I've installed the os x Yosemite theme on my Elementary OS but there are a few of the elements in the DE which does not seem to look good e.g. the menus on the wingpanel and slingsot items. I opened up the theme files and there is CSS styling. I can write CSS but how will I know which class or element to use as a selector? Although there are comments in the apps.css and gtk-widgets.css files which indicate the css for a few elements like slingshot but when i make change to them nothing happens.
Is there any tool available out there which can help me do this?
To debug the DE itself (I assume you want to debug a wingpanel widget), you need to somehow focus them. The easiest way I use is opening Slingshot (or any other wingpanel indicator), hovering your mouse over it and pressing Ctrl+Shift+I. The best position to hover your mouse over to inspect the slingshot widget is this little triangle (don't know the proper name for it):
Of course Ctrl+Shift+I will work only if gtk debugging is enabled.