Apple recently was granted US Design Patent D861,014 for an electronic device with graphical user interface. The patent is directed to the user interface for a smart watch. Below is figure 1.
Apple kept the time and date in solid lines claiming them rather than making the time and date in broken lines. Providing the date and time in broken lines would have made those elements unclaimed and would not have limited the claimed design.
However, including the date and time might not be much of a limitation in terms of the actual date and time displayed. First, any competitor device with the same vertical stripe pattern and time in the upper right location would show 10:09 twice a day. The old adage applies that a broken clock is correct twice a day. Further, it is likely that Wednesday will fall on the 23rd of the month every now and then.
Presenting the date and time in solid lines does limit the claimed design here. But maybe not greatly in terms of the actual time of 10:09 or the date of Wednesday the 23rd. Instead, the limitation probably is more in terms of the location and presentation of the date and time.
The original application that resulted in the above patent contained drawings showing the date and time in broken lines as well as solid lines. But, Apple amended the application to focus on the non-broken line version. There is a continuation patent application filed where Apple might be pursing the broken line version, which is shown below. If Apple obtains a patent on the broken line version below, it will have hedged its risk that the solid line version is too limiting.