An EmbeddableControl that implements IEditingCreateToolControl can be used for displaying Tool options within the Active Template pane as well as within the Template Properties Tools tab,

If the corresponding View must show differing information in the pane or tab, this can be handled by setting appropriate properties within InitializeForActiveTemplate and InitializeForTemplateProperties methods.

It's also possible to reuse the same EmbeddableControl and associated View for multiple Tools, which might be useful if several Tools have identical or very similar options. Each time the Initialize methods are called, the specified ToolOptions provides the current Tool ID as well as current Template, allowing the implementation to set appropriate properties.

The life-cycle of these controls is as follows

1. User opens the parent view - either TemplateProperties Tools tab, or Active Template pane
2. Either the default Tool is chosen or user clicks on a different Tool in the parent view
3. The View and control are constructed, View's DataContext is set to the control
4. InitializeForActiveTemplate or InitializeForTemplateProperties is called
5. ArcGIS.Desktop.Framework.Controls.EmbeddableControl.OpenAsync is called
6. User interacts with the view and control
7. User clicks another Tool in parent View, or closes the parent view
8. ArcGIS.Desktop.Framework.Controls.EmbeddableControl.CommitAsync is called
9. ArcGIS.Desktop.Framework.Controls.EmbeddableControl.CloseAsync is called

for additional functionality when processing common tool options of multiple templates within Template Properties

Reference

IEditingCreateToolControl Members
ArcGIS.Desktop.Editing Namespace
IEditingCreateToolMultiple Interface