To create filled arrowheads at the start or end of a line can be very tricky I have included the instruction for creating a filled arrowhead to the of a line object type.
1. First go to pen in the main menu select fill pattern in the drop down menu in this menu select none.
2. Go to back into the pen menu and in the drop down menu select fill color to black
3. Next open the edit object dialog screen. To open this menu go to window in the main menu and select edit object...
4. Draw a line and leave the line selected. Keeping the line select through the next steps is the key to adding a filled arrow head to the end of a line.
5. Once the line is drawn (making sure the line does not become deselected) in the edit object dialog screen select filled circle/chevron for either the start arrow or end arrow then select apply.
6. Now that this has been completed with the line still selected go to pen in the main menu and select fill pattern in the drop down menu and select the solid fill a new object will be created called a (polygon) this new item will automatically be selected.
7. With the new object selected in the edit object dialog screen select filled circle/chevron. This will place a filled arrow head at the end of the polygon.