WIP #4533

src/view/renderer.js

@@ -101,6 +101,13 @@ export default class Renderer {
 		 */
 		this.isFocused = false;
 
+		/**
+		 * Indicates if the view document is composing.
+		 *
+		 * @member {Boolean}
+		 */
+		this.isComposing = false;
+
 		/**
 		 * The text node in which the inline filler was rendered.
 		 *
@@ -762,6 +769,11 @@ export default class Renderer {
 	 * @returns {Boolean}
 	 */
 	_domSelectionNeedsUpdate( domSelection ) {
+		// Remain DOM selection untouched while composing (#1782)
+		if ( this.isComposing ) {
+			return false;
+		}
+
 		if ( !this.domConverter.isDomSelectionCorrect( domSelection ) ) {
 			// Current DOM selection is in incorrect position. We need to update it.
 			return true;

src/view/view.js

@@ -105,6 +105,7 @@ export default class View {
 		 */
 		this._renderer = new Renderer( this.domConverter, this.document.selection );
 		this._renderer.bind( 'isFocused' ).to( this.document );
+		this._renderer.bind( 'isComposing' ).to( this.document );
 
 		/**
 		 * A DOM root attributes cache. It saves the initial values of DOM root attributes before the DOM element