Clips out of numerical order in bins in browser

I am having a problem on FCP7 with clips in my browser. I don't understand why, but my clips have changed order. So in each named bin they used to be in numerical order, which I prefer. So for instance, a bin with 30 clips, all for the same card used to read coo1, coo2 coo3... They have all reordered them selves? Does anyone know how I can restore them to munerical order?

Click the heading in the Browser you want them sorted by.
Not sure if that's the issue, but we have to start somewhere, right?