I found that the unwanted mask outline will be displayed in Character Marker Symbol in ArcGIS 10.3 even if the ZERO value is set in outline width of Halo mask when the size of mask is smaller than 0.1.
My settings on ArcMap are shown as below:
Data Frame Properties:
In General tab,
Map > Meters
Display > Meters
Reference Scale > 1:1000 (Reference Scale must be set)
Label Engine > Standard Label Engine
In Symbol Property Editor> Character Marker tab
Type: Character Marker Symbol
Font: ESRI Default Marker
Subset: Basic Latin
Unicode:69 (means Cross symbol)
In Symbol Property Editor> Mask tab,
Size: 0.2 or smaller , e.g. 0.1
After I used the setting shown as above, the unwanted grey mask outline will be displayed even if I set the outline width to be zero and outline color to be white in color. For details, you may refer to the attached print-screen.
Does anyone know how to fix this problem? Thanks.