modelsim-altera had not updated result when you change the mif file in the RAM in QII

i made a test about simulating the RAM with .mif file

once it was ok when first time setup the mif file to RAM.
but when you changed one or more data of the mif during modelsim-altera is working，
you can found there is noting updated in the modelsim-altera simulation result. that was always same as the old mif flie。
no matter how many times you have recompiled the QII project or modelsim-altera project

and if you reboot （i mean close the modelsim-altera software and restart again） the result is updated.

i don't know why this was happened ，what is wrong between the QII and Modelsim-altera.

If i must reboot the software everytime,when mif file changed，i think that is so bad .....