diff --git a/app/views/units/_unit.html.erb b/app/views/units/_unit.html.erb
index b787939..008fa4f 100644
--- a/app/views/units/_unit.html.erb
+++ b/app/views/units/_unit.html.erb
@@ -1,7 +1,7 @@
 <tr id="<%= dom_id(unit) %>">
   <td class="<%= class_names('link', {subunit: unit.base}) %>">
     <%= link_to unit.symbol, edit_unit_path(unit), id: dom_id(unit, :edit),
-      data: {turbo_stream: true} %>
+      onclick: 'this.blur();', data: {turbo_stream: true} %>
   </td>
   <td><%= unit.name %></td>
   <td class="number"><%= scientifize(unit.multiplier) if unit.multiplier %></td>
diff --git a/test/application_system_test_case.rb b/test/application_system_test_case.rb
index 1031e7c..fab452d 100644
--- a/test/application_system_test_case.rb
+++ b/test/application_system_test_case.rb
@@ -28,6 +28,6 @@ class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
   end
 
   #def assert_stale(element)
-  #  assert_raise(Selenium::WebDriver::Error::StaleElementReferenceError) { element.tag_name }
+  #  assert_raises(Selenium::WebDriver::Error::StaleElementReferenceError) { element.tag_name }
   #end
 end
diff --git a/test/system/units_test.rb b/test/system/units_test.rb
index 213a694..5115d0d 100644
--- a/test/system/units_test.rb
+++ b/test/system/units_test.rb
@@ -22,9 +22,8 @@ class UnitsTest < ApplicationSystemTestCase
 
   test "add unit" do
     click_on t('units.index.add_unit')
-    assert_no_selector :link_or_button, text: t('units.index.add_unit')
 
-    within first('tbody > tr') do
+    within 'tbody > tr:has(input, textarea)' do
       assert_selector ':focus'
       maxlength = all(:fillable_field).to_h { |f| [f[:name], f[:maxlength].to_i || 1000] }
       fill_in 'unit[symbol]',
@@ -36,19 +35,63 @@ class UnitsTest < ApplicationSystemTestCase
       end
     end
 
-    within('tbody') do
+    within 'tbody' do
       assert_no_selector :fillable_field
       assert_selector 'tr', count: @user.units.count
     end
-    assert_selector :link_or_button, text: t('units.index.add_unit')
-    assert_selector '.flash.notice', text: t('units.create.success')
+    assert_selector '.flash.notice', exact_text: t('units.create.success')
   end
 
-  test "close new unit form with escape" do
+  test "add and edit disallow opening multiple forms" do
+    # Once new/edit form is open, other actions on the same page either replace
+    # the form or leave it untouched
+    # TODO: add non-empty form closing warning
+    links = {}
+    link_labels = {1 => [t('units.index.add_unit'), t('units.unit.add_subunit')],
+                   0 => units.map(&:symbol)}
+    link_labels.each_pair do |row_change, labels|
+      all(:link_or_button, exact_text: Regexp.union(labels)).map { |l| links[l] = row_change }
+    end
+    link, rows = links.assoc(links.keys.sample).tap { |l, _| links.delete(l) }
+    puts link[:text]
+    assert_difference ->{ all('tbody tr').count }, rows do
+      link.click
+    end
+    find 'tbody tr:has(input[type=text]:focus)'
+
+    # Link should be now unavailable or unclickable
+    begin
+      assert_raises(Selenium::WebDriver::Error::ElementClickInterceptedError) do
+        link.click
+      end if link.visible?
+    rescue Selenium::WebDriver::Error::StaleElementReferenceError
+      link = nil
+    end
+
+    link = links.keys.select(&:visible?).sample
+    assert_difference ->{ all('tbody tr').count }, links[link] - rows do
+      link.tap{|l| puts l[:text]}.click
+    end
+    assert_selector 'tbody tr:has(input[type=text]:focus)', count: 1
+  end
+
+  # NOTE: extend with any add/edit link
+  test "close new unit form with escape key" do
     click_on t('units.index.add_unit')
     first('tbody > tr').all(:field).sample.send_keys :escape
-    within('tbody') do
+    within 'tbody' do
       assert_no_selector :fillable_field
     end
   end
+
+  # NOTE: extend with any add/edit link
+  test "close and reopen new unit form" do
+    click_on t('units.index.add_unit')
+    within 'tbody' do
+      find(:link_or_button, exact_text: t(:cancel)).click
+      assert_no_selector :fillable_field
+    end
+    click_on t('units.index.add_unit')
+    assert_selector 'tbody > tr:has(input, textarea)'
+  end
 end