When I try to post a trade for buying australium weapons I am not able to select the strange option from drop down menu for the last weapon on right hand side of the trade(where we put items we want to buy). The problem is with only the last slot(8th slot). I am able to select strange option in other slots.

Here is an example to the trade I was trying to post -

http://www.tf2outpost.com/trade/27959370