Key legal question
Whether the exercise of previously granted purchase rights triggers the cantonal real estate transfer tax.
Extracted holding
Yes. Under cantonal practice, the tax is due upon exercise or transfer of the purchase right, not already upon its grant.
Extracted reasoning
A purchase right transfers significant disposal power, but taxing its grant would unduly restrict the federal civil-law institute. To avoid excessive interference with federal law, the canton taxes the right only when exercised or assigned to a third party.