# [✓] Locator constrained by polygon and NSolve

GROUPS:
 Dear Community,I have a polygon with a constrained locator in it. I would like to draw a horizontal line from the locator towards the left boundary of the polygon, which is also given by a stewise function called qgHSZ. I try to achieve this with NSolve, but I get some strange warnings, like "Part 2 of {0.5,10.} does not exist" Why?? "NSolve was unable to solve the system with inexact coeficients, etc." Not clear either. If I test NSolve below the plot, it works fine.What do I do wrong? Notebook attached. Tx for the kind help in advance, regards, Andras Attachments:
 This seems to work: DynamicModule[{pt = {0.5, qgHSZ[.2]}, from = .2, x}, {Graphics[{Dynamic[Line[{{from , pt[[2]]}, pt}]], LightBlue, Opacity[0.9], Polygon[pts], Locator[ Dynamic[pt , (pt = RegionNearest[Polygon[pts], #]; from = x /. NSolve[ qgHSZ[x] == pt[[2]], x][[1]]) &]]}, Axes -> True, AspectRatio -> 1], Dynamic[pt]}]