Type of bounding rectangle. 
By default the bounding rectangle is static (constant extents).
 Bounding rectangles can be changed to dynamic bounding rectangles which can grow horizontally or vertically. 
- Enumerator: 
 
| eDynamicBoundingRect_None  | 
 The bounding rectangle cannot grow.  
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| eDynamicBoundingRect_Horizontal  | 
 The bounding rectangle can grow horizontally.  
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| eDynamicBoundingRect_Vertical  | 
 The bounding rectangle can grow vertically.  
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