diff --git a/src/constrainteq.cpp b/src/constrainteq.cpp
index 985545c7..965a13d0 100644
--- a/src/constrainteq.cpp
+++ b/src/constrainteq.cpp
@@ -28,6 +28,50 @@ bool ConstraintBase::HasLabel() const {
     }
 }
 
+bool ConstraintBase::IsProjectible() const {
+    switch(type) {
+        case Type::POINTS_COINCIDENT:
+        case Type::PT_PT_DISTANCE:
+        case Type::PT_LINE_DISTANCE:
+        case Type::PT_ON_LINE:
+        case Type::EQUAL_LENGTH_LINES:
+        case Type::EQ_LEN_PT_LINE_D:
+        case Type::EQ_PT_LN_DISTANCES:
+        case Type::EQUAL_ANGLE:
+        case Type::LENGTH_RATIO:
+        case Type::LENGTH_DIFFERENCE:
+        case Type::SYMMETRIC:
+        case Type::SYMMETRIC_HORIZ:
+        case Type::SYMMETRIC_VERT:
+        case Type::SYMMETRIC_LINE:
+        case Type::AT_MIDPOINT:
+        case Type::HORIZONTAL:
+        case Type::VERTICAL:
+        case Type::ANGLE:
+        case Type::PARALLEL:
+        case Type::PERPENDICULAR:
+        case Type::WHERE_DRAGGED:
+        case Type::COMMENT:
+            return true;
+
+        case Type::PT_PLANE_DISTANCE:
+        case Type::PT_FACE_DISTANCE:
+        case Type::PROJ_PT_DISTANCE:
+        case Type::PT_IN_PLANE:
+        case Type::PT_ON_FACE:
+        case Type::EQUAL_LINE_ARC_LEN:
+        case Type::DIAMETER:
+        case Type::PT_ON_CIRCLE:
+        case Type::SAME_ORIENTATION:
+        case Type::CUBIC_LINE_TANGENT:
+        case Type::CURVE_CURVE_TANGENT:
+        case Type::ARC_LINE_TANGENT:
+        case Type::EQUAL_RADIUS:
+            return false;
+    }
+    ssassert(false, "Impossible");
+}
+
 ExprVector ConstraintBase::VectorsParallel3d(ExprVector a, ExprVector b, hParam p) {
     return a.Minus(b.ScaledBy(Expr::From(p)));
 }
diff --git a/src/describescreen.cpp b/src/describescreen.cpp
index 4ebe20e5..f17baaa1 100644
--- a/src/describescreen.cpp
+++ b/src/describescreen.cpp
@@ -40,6 +40,16 @@ void TextWindow::ScreenSetTtfFont(int link, uint32_t v) {
     SS.ScheduleShowTW();
 }
 
+void TextWindow::ScreenConstraintToggleReference(int link, uint32_t v) {
+    hConstraint hc = { v };
+    Constraint *c = SK.GetConstraint(hc);
+
+    SS.UndoRemember();
+    c->reference = !c->reference;
+
+    SS.ScheduleShowTW();
+}
+
 void TextWindow::ScreenConstraintShowAsRadius(int link, uint32_t v) {
     hConstraint hc = { v };
     Constraint *c = SK.GetConstraint(hc);
@@ -365,16 +375,45 @@ void TextWindow::DescribeSelection() {
         Printf(false, "%FtSELECTED:%E comment text");
     } else if(gs.n == 0 && gs.constraints == 1) {
         Constraint *c = SK.GetConstraint(gs.constraint[0]);
+        const std::string &desc = c->DescriptionString().c_str();
 
-        if(c->type == Constraint::Type::DIAMETER) {
-            Printf(false, "%FtDIAMETER CONSTRAINT");
-
-            Printf(true, "  %Fd%f%D%Ll%s  show as radius",
-                   &ScreenConstraintShowAsRadius, gs.constraint[0].v,
-                   c->other ? CHECK_TRUE : CHECK_FALSE);
+        if(c->type == Constraint::Type::COMMENT) {
+            Printf(false, "%FtCOMMENT%E  %s", desc.c_str());
+        } else if(c->HasLabel()) {
+            if(c->reference) {
+                Printf(false, "%FtREFERENCE%E  %s", desc.c_str());
+            } else {
+                Printf(false, "%FtDIMENSION%E  %s", desc.c_str());
+            }
+            Printf(true, "  %Fd%f%D%Ll%s  reference",
+                   &ScreenConstraintToggleReference, gs.constraint[0].v,
+                   c->reference ? CHECK_TRUE : CHECK_FALSE);
+            if(c->type == Constraint::Type::DIAMETER) {
+                Printf(false, "  %Fd%f%D%Ll%s  use radius",
+                       &ScreenConstraintShowAsRadius, gs.constraint[0].v,
+                       c->other ? CHECK_TRUE : CHECK_FALSE);
+            }
         } else {
-            Printf(false, "%FtSELECTED:%E %s",
-            c->DescriptionString().c_str());
+            Printf(false, "%FtCONSTRAINT%E  %s", desc.c_str());
+        }
+
+        if(c->IsProjectible()) {
+            if(c->workplane == Entity::FREE_IN_3D) {
+                Printf(true, "%FtNOT PROJECTED TO WORKPLANE%E");
+            } else {
+                Entity *w = SK.GetEntity(c->workplane);
+                if(w->h.isFromRequest()) {
+                    Printf(true, "%FtIN WORKPLANE%E  %Fl%Ll%D%f%h%s%E",
+                        w->h.request().v,
+                        (&TextWindow::ScreenSelectRequest), &(TextWindow::ScreenHoverRequest),
+                        w->DescriptionString().c_str());
+                } else {
+                    Printf(true, "%FtIN WORKPLANE%E  %Fl%Ll%D%f%h%s%E",
+                        w->h.group().v,
+                        (&TextWindow::ScreenSelectGroup), (&TextWindow::ScreenHoverGroupWorkplane),
+                        w->DescriptionString().c_str());
+                }
+            }
         }
 
         std::vector<hEntity> lhe = {};
@@ -391,16 +430,20 @@ void TextWindow::DescribeSelection() {
         lhe.erase(it, lhe.end());
 
         if(!lhe.empty()) {
-            Printf(true, "%FtCONSTRAINS:%E");
+            if(c->reference) {
+                Printf(true, "%FtMEASURES:%E");
+            } else {
+                Printf(true, "%FtCONSTRAINS:%E");
+            }
 
             int a = 0;
             for(hEntity he : lhe) {
-                Request *r = SK.GetRequest(he.request());
-                std::string s = r->DescriptionString();
+                Entity *e = SK.GetEntity(he);
                 Printf(false, "%Bp   %Fl%Ll%D%f%h%s%E",
                     (a & 1) ? 'd' : 'a',
-                    r->h.v, (&TextWindow::ScreenSelectRequest),
-                    &(TextWindow::ScreenHoverRequest), s.c_str());
+                    e->h.v, (&TextWindow::ScreenSelectEntity),
+                    &(TextWindow::ScreenHoverEntity),
+                    e->DescriptionString().c_str());
                 a++;
             }
         }
diff --git a/src/sketch.h b/src/sketch.h
index 72cda7eb..95aebd05 100644
--- a/src/sketch.h
+++ b/src/sketch.h
@@ -703,6 +703,7 @@ public:
     }
 
     bool HasLabel() const;
+    bool IsProjectible() const;
 
     void Generate(IdList<Param, hParam> *param);
 
diff --git a/src/ui.h b/src/ui.h
index 8f29a73c..a29bad1c 100644
--- a/src/ui.h
+++ b/src/ui.h
@@ -397,6 +397,7 @@ public:
     static void ScreenUnselectAll(int link, uint32_t v);
 
     // when we're describing a constraint
+    static void ScreenConstraintToggleReference(int link, uint32_t v);
     static void ScreenConstraintShowAsRadius(int link, uint32_t v);
 
     // and the rest from the stuff in textscreens.cpp