[FIX] mail: fix text selection in composer using SHIFT and arrow keys

This commit corrects the faulty SHIFT + ArrowKey selection behavior.

task-2388650

closes odoo/odoo#62251

X-original-commit: d498f899aa2ef81acbcd035896b9fcc912e4d52b
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

addons/mail/static/src/components/composer_text_input/composer_text_input.js

@@ -97,8 +97,9 @@ class ComposerTextInput extends Component {
     saveStateInStore() {
         this.composer.update({
             textInputContent: this._getContent(),
-            textInputCursorStart: this._getSelectionStart(),
             textInputCursorEnd: this._getSelectionEnd(),
+            textInputCursorStart: this._getSelectionStart(),
+            textInputSelectionDirection: this._textareaRef.el.selectionDirection,
         });
     }
 
@@ -159,7 +160,8 @@ class ComposerTextInput extends Component {
         this._textareaRef.el.value = this.composer.textInputContent;
         this._textareaRef.el.setSelectionRange(
             this.composer.textInputCursorStart,
-            this.composer.textInputCursorEnd
+            this.composer.textInputCursorEnd,
+            this.composer.textInputSelectionDirection,
         );
         this._updateHeight();
     }

addons/mail/static/src/models/composer/composer.js

@@ -45,6 +45,9 @@ function factory(dependencies) {
         }
 
         detectSuggestionDelimiter() {
+            if (this.textInputCursorStart !== this.textInputCursorEnd) {
+                return;
+            }
             const lastInputChar = this.textInputContent.substring(this.textInputCursorStart - 1, this.textInputCursorStart);
             const suggestionDelimiters = ['@', ':', '#', '/'];
             if (suggestionDelimiters.includes(lastInputChar) && !this.hasSuggestions) {
@@ -1043,6 +1046,9 @@ function factory(dependencies) {
         textInputCursorStart: attr({
             default: 0,
         }),
+        textInputSelectionDirection: attr({
+            default: "none",
+        }),
         thread: one2one('mail.thread', {
             inverse: 'composer',
         }),