Isn't there a way to customize my holdings view in each account?

In the new Dashboard asset allocation panel, Quicken is using data from a third-party quote provider to "drill down" into each mutual fund/ETF to calculate the proper asset class allocation of each fund. So if you have a fund which holds 50% domestic stocks, 10% foreign stocks and 40% domestic bonds, it applied those percentages to your holdings in the fund. This is why it is changing many funds to "mixed assets"; even if a fund is 98% stocks and 2% mutual funds, it's a mixed asset.

That said, the problem we have is that they made this change for the new Dashboard, but they did not make the change for the Portfolio window's asset allocation. The product manager has said this will follow; they just didn't want to change everything at once. So until version 6.4 or whenever, we're in an in-between state where the Portfolio screen asset allocation is not particularly useful.