It is possible, when hints from the control below is cover currently edited attribute control.
Need avoid this situation.
Main idea make tooltips like in cocoa. If user start type text in entry tooltip should be hide.
But it conserns not only elm_entry. Simular problem have other widgets, if click on button tooltip
still show, but in other widget toolkits (I was tested qt and gtk+) a tooltip is hide.
Resume: hide tooltip on widget click, and on type text in entry.