diff --git a/lib/src/view/design_main_strand_creating.dart b/lib/src/view/design_main_strand_creating.dart
index f0faf85c..4842f460 100644
--- a/lib/src/view/design_main_strand_creating.dart
+++ b/lib/src/view/design_main_strand_creating.dart
@@ -49,7 +49,6 @@ class DesignMainStrandCreatingComponent extends UiComponent2<DesignMainStrandCre
         ..y1 = '${start_svg.y}'
         ..x2 = '${end_svg.x}'
         ..y2 = '${end_svg.y}'
-        ..key = 'line'
         ..className = constants.css_selector_domain)(),
       (End5Prime()
         ..classname = classname_5p
diff --git a/lib/src/view/design_main_strand_dna_end_moving.dart b/lib/src/view/design_main_strand_dna_end_moving.dart
index 2a967c51..4d428860 100644
--- a/lib/src/view/design_main_strand_dna_end_moving.dart
+++ b/lib/src/view/design_main_strand_dna_end_moving.dart
@@ -70,7 +70,6 @@ class EndMovingComponent extends UiComponent2<EndMovingProps> {
     if (!props.render) {
       return null;
     }
-    DNAEnd dna_end = props.dna_end!;
     Helix helix = props.helix!;
     int current_offset = props.current_offset!;
     bool forward = props.forward!;
diff --git a/lib/src/view/design_main_strand_extension.dart b/lib/src/view/design_main_strand_extension.dart
index b685b447..68851423 100644
--- a/lib/src/view/design_main_strand_extension.dart
+++ b/lib/src/view/design_main_strand_extension.dart
@@ -229,7 +229,7 @@ class DesignMainExtensionComponent extends UiComponent2<DesignMainExtensionProps
         'change extension number of bases',
         current_num_bases: props.ext.num_bases,
         lower_bound: 1));
-    if (new_num_bases == null || new_num_bases == props.ext.num_bases) {
+    if (new_num_bases == props.ext.num_bases) {
       return;
     }
     var selected_extensions = app.state.ui_state.selectables_store.selected_extensions;
diff --git a/lib/src/view/design_main_strand_insertion.dart b/lib/src/view/design_main_strand_insertion.dart
index fb9be467..8ef999ba 100644
--- a/lib/src/view/design_main_strand_insertion.dart
+++ b/lib/src/view/design_main_strand_insertion.dart
@@ -167,18 +167,18 @@ class DesignMainStrandInsertionComponent extends UiComponent2<DesignMainStrandIn
 
     return (Dom.g()..key = key)(
         (Dom.rect()
-          ..x = background_x
-          ..y = background_y
-          ..width = background_width
-          ..height = background_height
-          ..className = 'insertion-background'
-          // ..onClick = ((_) => change_insertion_length())
-          ..key = 'rect')(),
+              ..x = background_x
+              ..y = background_y
+              ..width = background_width
+              ..height = background_height
+              ..className = 'insertion-background'
+            // ..onClick = ((_) => change_insertion_length())
+            )(),
         (Dom.text()
-          // ..onClick = ((_) => change_insertion_length())
-          ..dy = dy_text
-          // ..id = props.selectable_insertion.id()
-          ..key = 'text')(text_path_props('${length}')));
+              // ..onClick = ((_) => change_insertion_length())
+              ..dy = dy_text
+            // ..id = props.selectable_insertion.id()
+            )(text_path_props('${length}')));
   }
 
   ReactElement _insertion_background(Point<double> pos) {
diff --git a/lib/src/view/design_main_strands_moving.dart b/lib/src/view/design_main_strands_moving.dart
index c6035b8d..c66386c3 100644
--- a/lib/src/view/design_main_strands_moving.dart
+++ b/lib/src/view/design_main_strands_moving.dart
@@ -41,7 +41,6 @@ DesignMainStrandsMovingProps set_design_main_strands_moving_props(
     ..side_selected_helix_idxs = state.ui_state.side_selected_helix_idxs
     ..helix_idx_to_svg_position_map = state.helix_idx_to_svg_position_map
     ..geometry = state.design.geometry;
-  ;
 }
 
 UiFactory<DesignMainStrandsMovingProps> ConnectedDesignMainStrandsMoving =
diff --git a/lib/src/view/design_side_helix.dart b/lib/src/view/design_side_helix.dart
index 4fb98796..d617ab72 100644
--- a/lib/src/view/design_side_helix.dart
+++ b/lib/src/view/design_side_helix.dart
@@ -21,6 +21,7 @@ import 'helix_context_menu.dart';
 part 'design_side_helix.over_react.g.dart';
 
 const String SIDE_VIEW_PREFIX = 'side-view';
+const SHOW_HELIX_COORDINATES_INSTEAD_OF_IDX = false;
 
 UiFactory<DesignSideHelixProps> DesignSideHelix = _$DesignSideHelix;
 
@@ -51,7 +52,6 @@ class DesignSideHelixComponent extends UiComponent2<DesignSideHelixProps> with P
     // set SHOW_HELIX_COORDINATES_INSTEAD_OF_IDX to true to print helix coordinates in side view instead
     // of idx, which is useful for making figures in the documentation showing how the grids work
 //    bool SHOW_HELIX_COORDINATES_INSTEAD_OF_IDX = true;
-    bool SHOW_HELIX_COORDINATES_INSTEAD_OF_IDX = false;
     int precision = constants.NUM_DIGITS_PRECISION_POSITION_DISPLAYED;
 
     String grid_position_str;
@@ -86,7 +86,7 @@ backbone angles at current slice bar offset = ${props.slice_bar_offset}:
         ..r = '${props.helix.geometry.helix_radius_svg}'
         ..onClick = ((e) => this._handle_click(e, props.helix))
         ..id = helix_circle_id()
-        ..key = 'circle')((Dom.svgTitle()..key = 'circle-tooltip')(tooltip)),
+        ..key = 'circle')((Dom.svgTitle())(tooltip)),
       (Dom.text()
             ..style = SHOW_HELIX_COORDINATES_INSTEAD_OF_IDX ? {'fontSize': 20} : {}
             ..className = '$SIDE_VIEW_PREFIX-helix-text'
@@ -94,7 +94,7 @@ backbone angles at current slice bar offset = ${props.slice_bar_offset}:
             ..onClick = ((e) => this._handle_click(e, props.helix))
             ..key = 'text-idx')(
           SHOW_HELIX_COORDINATES_INSTEAD_OF_IDX ? grid_position_str : props.helix.idx.toString(),
-          (Dom.svgTitle()..key = 'text-idx-tooltip')(tooltip)),
+          (Dom.svgTitle())(tooltip)),
       if (props.show_grid_coordinates)
         (Dom.text()
           ..fontSize = 10
diff --git a/lib/src/view/potential_crossover_view.dart b/lib/src/view/potential_crossover_view.dart
index 9171e553..b00d37c0 100644
--- a/lib/src/view/potential_crossover_view.dart
+++ b/lib/src/view/potential_crossover_view.dart
@@ -11,7 +11,6 @@ PotentialCrossoverViewProps set_potential_crossover_props(
   return elt
     ..potential_crossover = potential_crossover
     ..id_ = 'potential-crossover-main';
-  ;
 }
 
 UiFactory<PotentialCrossoverViewProps> ConnectedPotentialCrossoverView =
diff --git a/lib/src/view/strand_color_picker.dart b/lib/src/view/strand_color_picker.dart
index 03087304..ef875804 100644
--- a/lib/src/view/strand_color_picker.dart
+++ b/lib/src/view/strand_color_picker.dart
@@ -106,9 +106,7 @@ class StrandOrSubstrandColorPickerComponent
             'color': state.color ?? props.color,
             'onChangeComplete': handleOnChangeComplete,
           }),
-          (Dom.span()
-            ..className = 'dialog-buttons'
-            ..key = 'buttons')(
+          (Dom.span()..className = 'dialog-buttons')(
             (Dom.input()
               ..type = 'submit'
               ..value = 'OK'
diff --git a/lib/src/view/view.dart b/lib/src/view/view.dart
index 126655fb..4011fd06 100644
--- a/lib/src/view/view.dart
+++ b/lib/src/view/view.dart
@@ -134,9 +134,6 @@ class View {
 
   set_design_oxview_pane_widths() {
     String design_width = local_storage.design_width();
-    if (design_width == null) {
-      design_width = '${constants.default_design_width_percent}%';
-    }
     num oxview_width_int = 100.0 - num.parse(design_width.substring(0, design_width.length - 1));
     String oxview_width = '${oxview_width_int.toString()}%';
     design_and_modes_buttons_container_element.setAttribute('style', 'width: $design_width');