Why are both locators moving?

*To*: mathgroup at smc.vnet.net*Subject*: [mg115230] Why are both locators moving?*From*: Dims <dims12 at hotmail.com>*Date*: Tue, 4 Jan 2011 18:49:50 -0500 (EST)

In the code below I expect that locators can be moved independently, but actually locator p1 causes locator p2 to move too if both conditions occure: 1) any "Plot" instruction presents within Show 2) a=p1; presents within Dynamic p1 = {0, 0} p2 = {0, 1} Dynamic[ a = p1; (* condition 1 *) Show[ Plot[Cos[b],{b,1,2}], (* condition 2 *) Graphics[Line[{{0, 0}, {1, 1}}]], Graphics[Locator[Dynamic[p1]]], Graphics[Locator[Dynamic[p2]]], PlotRange -> {{-10, 10}, {-1, 1}}, Axes -> True, AspectRatio -> 1 ] ] My question is: why? Is it a bug or by-design behavior? Where is the value for p2 assigned? How to make both locators move independently along with plot?