Nibal,
It looks like everything is working based on the files you sent in. The portion of mainline not sizing is because the pipes did not have any flow or pressure downstream of your last valve, where the pipe is simply connected into a shut-off valve. Since this shut-off valve was indicating the tie in to another floor, you could have used a CAP to indicate the other floors demands, and the system would have sized the pipes just fine.
As far as the use of match properties on the unsized pipe to enable the use of the pipe label tool, that is fine, but just know there were no crosschecks that the system did to ensure the size you matched will work on those sections of pipe based on the real demands needed for those sections of pipe.
As explained in your ticket response, the Highlight tool functions in a few different ways-
1: When clicking on items that are connected to other items (heads piped together, or pipe connected together), everything will highlight to show what is connected.
2: When clicking on single items (not connected to anything), only that type of item will be highlighted through the plan. So, if there is no other unsized pipes except the one you are clicking on, then only that one will highlight. If you want to highlight a certain size of pipe in the drawing, you will need to make sure there is a single section of pipe not connected to anything, edit that section to the desired size, then use highlight.
If you need anything else, or I have misunderstood what you are after, just let us know and we would be happy to help you out.