Test bug with calc() and mixing units on IE9 ?
Update: NOT A BUG. Good to know: the css calc() function requires '+' and '-' operators to be surrounded by whitespaces to work.
by gudoy
HTML
<div id="parent">
<div>
<div id="t1"></div>
</div>
<div>
<div id="t2"></div>
<div id="t3"></div>
</div>
</div>
CSS
#parent { width:200px; border:1px solid red; }
#t1 { width:100px; height:20px; background:orange; }
#t2 { width:-webkit-calc(50% - 2px); width:calc(50% - 2px); height:20px; display:inline-block; background:blue; }
#t3 { width:-webkit-calc(50% - 2px); width:calc(50% - 2px); height:20px; display:inline-block; background:green; }