Stacked Bar chart with continuous scale

[simonaubert]

Hello all,

I have an issue that seems pretty easy : 
Doing a bar chart with two dimensions : one date in continuous scale, a category

The thing is almost done but it's just impossible to sort the bar and the legend by the logic order.

(and yes, I need custom colors)

And the issue : 

I don't have the exact translation in English but basically I cannot sort because a contiunous axis is used. I don't understand the logic at all, there.  Why is there even an impact?

I need the continuous scale because the whole chart is the length of an agile iteration... so that, I know where I am (in my exemple, I am at 80% of the iteration).

Best regards,

Simon