Many reports have important features - such as the switch that controls which style of report to display - accessible only through icons that are hidden except during mouse-over. This makes the features nearly impossible to discover without being told out-of-band of their existence. It's especially a problem on some phone and tablet interfaces where users may not be able to move the "mouse" pointer without registering a click.
On this screen, the green icons for configuring the style of the report only appear when the mouse pointer is within the white rectangle containing the report. The "help" and "thumbs up" icons next to the title "Social Networks" appear only when the mouse pointer is in that rectangle and on about the same horizontal level as the title. The "thumbs down" icon is especially evil: it does not appear until the mouse is hovering over the "thumbs up" icon. There are also per-row icons for things like "row evolution" which will only appear with the mouse over the row in question.
There is no legitimate reason for these icons to ever be hidden at all, and they shouldn't ever be hidden. But at the very least, the config icons at the bottom should not be hidden. They appear in what otherwise looks like unused visual space and there's no reason for someone to expect icons in that location unless previously told about their existence. They are easy to miss. The others at least can be argued to be relevant to specific items and located near those items in places users might expect to look - although such an argument is weak.
Thanks for the feedback @mskala
We quite like a clean UI as if we were to show all the icons all the time it would be quite bloated/messy. Eg the thumbs up/down it's totally fine if people only discover this by accident / experience for us as they aren't too important. This is different though for some other features. For the mobile version we could definitely improve this though and eventually show more icons without needing to hover.
A blank white page with nothing on it would be even more "clean." I prefer a usable UI.