This is something to do with the style="float:left"
If I do not apply float:left
on the second div, problem reproduces with Tooltips not coming sometimes on first Div's chart and sometimes not even on both charts.
Check the Fiddle at:
Edit: Also can you please tell me, as per my supplied Fiddle;
Can I start CategoryAxis from Feb 26? I mean Feb 26 is coming a bit ahead but I want to be close to 0.