I made an assembly. I intentionally changed the appearance of one part and then the feature manager tree in assembly don't show features performed on parts. Also a blue sign appeared on every part. How can i solve this problem? Kindly check out the attached pic and file
These parts in lightweight mode and hence you see no features.
You have not uploaded part files with the assembly so assembly can't be resolved. But you need to set lightweight to resolved mode.
Simply right click on assembly name in the feature tree and select "Set lightweight to resolved"