gistfile1.as

var dict = new Dictionary;
dict[flash.display.ActionScriptVersion] = true;
var isFirstRun = true;
for (var key in dict) {
trace('key = ' + key);
  if (isFirstRun) {
		dict[flash.display.AVM1Movie] = true;
		isFirstRun = false;
	}
	delete dict[key];
}
trace("dict[flash.display.AVM1Movie] = " + dict[flash.display.AVM1Movie]);
trace("dict[flash.display.ActionScriptVersion] = " + dict[flash.display.ActionScriptVersion]);

trace('======');

var dict = new Dictionary;
dict[flash.display.AVM1Movie] = true;
var isFirstRun = true;
for (var key in dict) {
trace('key = ' + key);
	if (isFirstRun) {
		dict[flash.display.ActionScriptVersion] = true;
		isFirstRun = false;
	}
	delete dict[key];
}
trace("dict[flash.display.AVM1Movie] = " + dict[flash.display.AVM1Movie]);
trace("dict[flash.display.ActionScriptVersion] = " + dict[flash.display.ActionScriptVersion]);

/*

key = [class ActionScriptVersion]
dict[flash.display.AVM1Movie] = true
dict[flash.display.ActionScriptVersion] = undefined
======
key = [class AVM1Movie]
key = [class ActionScriptVersion]
dict[flash.display.AVM1Movie] = undefined
dict[flash.display.ActionScriptVersion] = undefined

*/