after 9000 hours it finally works

src/components/settings_modal/settings_modal_user_content.js

@@ -88,6 +88,12 @@ const SettingsModalContent = {
       // Clear the state of target tab, so that next time settings is opened
       // it doesn't force it.
       useInterfaceStore().clearSettingsModalTargetTab()
+    },
+    nestedTooBig () {
+      this.$refs.tabSwitcher.showNav()
+    },
+    nestedTooSmall () {
+      this.$refs.tabSwitcher.hideNav()
     }
   },
   mounted () {

src/components/settings_modal/settings_modal_user_content.vue

@@ -2,24 +2,33 @@
   <vertical-tab-switcher
     ref="tabSwitcher"
     class="settings_tab-switcher"
-    :side-tab-bar="true"
     :scrollable-tabs="true"
     :body-scroll-lock="bodyLock"
   >
     <div
+      :full-width="true"
       :label="$t('settings.general')"
       icon="wrench"
       data-tab-name="general"
     >
-      <GeneralTab />
+      <GeneralTab
+        class="inner-tab -middle"
+        @too-small="() => nestedTooSmall()"
+        @too-big="() => nestedTooBig()"
+      />
     </div>
     <div
+      :full-width="true"
       :label="$t('settings.appearance')"
       icon="window-restore"
       data-tab-name="appearance"
       :delay-render="true"
     >
-      <AppearanceTab />
+      <AppearanceTab
+        class="inner-tab -middle"
+        @too-small="() => nestedTooSmall()"
+        @too-big="() => nestedTooBig()"
+      />
     </div>
     <div
       v-if="expertLevel > 0"

src/components/settings_modal/tabs/appearance_tab.vue

@@ -5,6 +5,8 @@
     ref="tabSwitcher"
     :side-tab-bar="true"
     :scrollable-tabs="true"
+    @too-small="() => console.log('small') || $emit('tooSmall')"
+    @too-big="() => $emit('tooBig')"
   >
     <div
       :label="$t('settings.interface')"

src/components/settings_modal/tabs/general_tab.vue

@@ -3,6 +3,8 @@
     :label="$t('settings.general')"
     ref="tabSwitcher"
     class="settings_tab-switcher"
+    @too-small="() => $emit('tooSmall')"
+    @too-big="() => $emit('tooBig')"
   >
     <div
       :label="$t('settings.behavior')"