Fix a crash; it was possible to attempt to draw in a workplane

that's in a group that solves after the current group. This means
that the constraint/request gets deleted instantly, and stuff like
auto-constraints on the just-created entities blow up. I now check
that the active workplane comes from the active group or one solved
before it.

[git-p4: depot-paths = "//depot/solvespace/": change = 1729]

constraint.cpp

@@ -6,11 +6,10 @@ char *Constraint::DescriptionString(void) {
     return ret;
 }
 
-hConstraint Constraint::AddConstraint(Constraint *c) {
+void Constraint::AddConstraint(Constraint *c) {
     SS.constraint.AddAndAssignId(c);
 
     SS.GW.GeneratePerSolving();
-    return c->h;
 }
 
 void Constraint::Constrain(int type, hEntity ptA, hEntity ptB, hEntity entityA)

graphicswin.cpp

@@ -237,11 +237,20 @@ void GraphicsWindow::EnsureValidActives(void) {
     }
 
     // The active coordinate system must also exist.
-    if(activeWorkplane.v != Entity::FREE_IN_3D.v && 
-                       !SS.entity.FindByIdNoOops(activeWorkplane))
-    {
-        activeWorkplane = Entity::FREE_IN_3D;
-        change = true;
+    if(activeWorkplane.v != Entity::FREE_IN_3D.v) {
+        Entity *e = SS.entity.FindByIdNoOops(activeWorkplane);
+        if(e) {
+            hGroup hgw = e->group;
+            if(hgw.v != activeGroup.v && SS.GroupsInOrder(activeGroup, hgw)) {
+                // The active workplane is in a group that comes after the
+                // active group; so any request or constraint will fail.
+                activeWorkplane = Entity::FREE_IN_3D;
+                change = true;
+            }
+        } else {
+            activeWorkplane = Entity::FREE_IN_3D;
+            change = true;
+        }
     }
 
     bool in3d = (activeWorkplane.v == Entity::FREE_IN_3D.v);
@@ -322,7 +331,6 @@ void GraphicsWindow::MenuRequest(int id) {
             SS.GW.GroupSelection();
             if(SS.GW.gs.n == 1 && SS.GW.gs.workplanes == 1) {
                 SS.GW.activeWorkplane = SS.GW.gs.entity[0];
-                SS.GW.ClearSelection();
             }
 
             if(SS.GW.activeWorkplane.v == Entity::FREE_IN_3D.v) {
@@ -335,7 +343,7 @@ void GraphicsWindow::MenuRequest(int id) {
             Quaternion quatf = e->Normal()->NormalGetNum();
             Vector offsetf = (e->WorkplaneGetOffset()).ScaledBy(-1);
             SS.GW.AnimateOnto(quatf, offsetf);
-            SS.GW.EnsureValidActives();
+            SS.GW.ClearSuper();
             SS.TW.Show();
             break;
         }

sketch.h

@@ -372,7 +372,7 @@ public:
 
     char *DescriptionString(void);
 
-    static hConstraint AddConstraint(Constraint *c);
+    static void AddConstraint(Constraint *c);
     static void MenuConstrain(int id);
     
     struct {

textwin.cpp

@@ -292,6 +292,7 @@ void TextWindow::ScreenActivateGroup(int link, DWORD v) {
         // workplane too.
         SS.GW.activeWorkplane = g->h.entity(0);
     }
+    SS.GW.ClearSuper();
 }
 void TextWindow::ShowListOfGroups(void) {
     Printf(true, "%Ftactive  show  group-name%E");