Reset player.current_prestroke if we deleted last prestroke of theirs

client/webgl_geometry.js

@@ -250,6 +250,10 @@ function geometry_clear_oldest_prestroke(state, context, player_id) {
     const player = state.players[player_id];
     player.strokes.shift();
 
+    if (player.strokes.length === 0) {
+        player.current_prestroke = false;
+    }
+
     recompute_dynamic_data(state, context);
 }
 
@@ -259,6 +263,10 @@ function geometry_clear_newest_prestroke(state, context, player_id) {
     const player = state.players[player_id];
     player.strokes.pop();
 
+    if (player.strokes.length === 0) {
+        player.current_prestroke = false;
+    }
+
     recompute_dynamic_data(state, context);
 }