I've covered a raspberry pi gpio header with a silk rectangle. The result is something like this, being the yellow layer the silk:

But, when I edit some parts or change the layer edit selector the all the vias disappear under the silk:

In the photo view the results look like this, which I don't like because it looks like the copper of the via is completely covered with silk:

Is there something I'm doing wrong? I'm just filling a rectangle over the vias and then let the program to handle it automatically.
Electron
3.0.11
Windows
10
EasyEDA
6.2.43