Feature: loading preview, better text popup preview (#8011)

src-ui/src/app/data/document.ts

@@ -150,6 +150,8 @@ export interface Document extends ObjectWithPermissions {
 
   added?: Date
 
+  mime_type?: string
+
   deleted_at?: Date
 
   original_file_name?: string

src-ui/src/app/data/ui-settings.ts

@@ -61,6 +61,8 @@ export const SETTINGS_KEYS = {
   DEFAULT_PERMS_EDIT_GROUPS: 'general-settings:permissions:default-edit-groups',
   DOCUMENT_EDITING_REMOVE_INBOX_TAGS:
     'general-settings:document-editing:remove-inbox-tags',
+  DOCUMENT_EDITING_OVERLAY_THUMBNAIL:
+    'general-settings:document-editing:overlay-thumbnail',
   SEARCH_DB_ONLY: 'general-settings:search:db-only',
   SEARCH_FULL_TYPE: 'general-settings:search:more-link',
   EMPTY_TRASH_DELAY: 'trash_delay',
@@ -229,6 +231,11 @@ export const SETTINGS: UiSetting[] = [
     type: 'boolean',
     default: false,
   },
+  {
+    key: SETTINGS_KEYS.DOCUMENT_EDITING_OVERLAY_THUMBNAIL,
+    type: 'boolean',
+    default: true,
+  },
   {
     key: SETTINGS_KEYS.SEARCH_DB_ONLY,
     type: 'boolean',