Determine whether to show this query:
Global context (no selection or heap available)
any context arg - disallow
Local context
context arg doesn't match available context - disallow
no context arg and no heap arg - disallow (no point in operating on a selection)
Policy() -
Constructor for class org.eclipse.mat.ui.internal.browser.Policy
pop() -
Method in class org.eclipse.mat.parser.internal.util.IntStack