The View Horizontal Annotation command assigns a Feature Style to the alignment point as Petr says.
Under Tools menu, the Style Manager defines that Style or simply assigns a Named Symbology to the Style.
Under Tools menu, the Named Symbology Manager defines the symbology that will be used to display the alignment point. It defines how point line and text are to be displayed in MicroStation. From your screen shot I would assume your Named Symbology for the alignment points is defined to display a Symbol and the symbol to be displayed is the Plus Sign.
Bentley has a tutorial for basic InRoads online somewhere. It describes the graphic display - feature - STyle -Symbology relationship. If you are a Select customer it should be avasilable to you for download.