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1. The Grid has a default maximum of 10000 lines that is controlled via a new property. The grid is not created (is empty)
if a higher number of lines is necessary. This event is show as a Warning in the Report view.
2. The Grid now checks a new property ShowOnlyInEditMode before deciding whether to show the grid or not. This is a new
mode for ViewProvider2D and derived objects. If the property is set to true (and showGrid is true), the grid is only shown
if the object is in edit mode. If the property is set to false, the grid is shown regardless of whether it is in edit mode
or not (provided that showGrid is true).
3. Grid limits are now encapsulated (private). They can be set via a new function updateGridExtent.
