Composition should end if we have selection.

Source/core/paint/InlineTextBoxPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/InlineTextBoxPainter.h"
 
 #include "core/dom/DocumentMarkerController.h"
 #include "core/dom/RenderedDocumentMarker.h"
 #include "core/editing/CompositionUnderline.h"
@@ skipping 59 matching lines @@
     bool isPrinting = m_inlineTextBox.layoutObject().document().printing();
 
     // Determine whether or not we're selected.
     bool haveSelection = !isPrinting && paintInfo.phase != PaintPhaseTextClip && m_inlineTextBox.selectionState() != LayoutObject::SelectionNone;
     if (!haveSelection && paintInfo.phase == PaintPhaseSelection) {
         // When only painting the selection, don't bother to paint if there is none.
         return;
     }
 
     // Determine whether or not we have composition underlines to draw.
-    bool containsComposition = m_inlineTextBox.layoutObject().node() && m_inlineTextBox.layoutObject().frame()->inputMethodController().compositionNode() == m_inlineTextBox.layoutObject().node();
+    bool containsComposition = !haveSelection && m_inlineTextBox.layoutObject().node() && m_inlineTextBox.layoutObject().frame()->inputMethodController().compositionNode() == m_inlineTextBox.layoutObject().node();
     bool useCustomUnderlines = containsComposition && m_inlineTextBox.layoutObject().frame()->inputMethodController().compositionUsesCustomUnderlines();
 
     // The text clip phase already has a DrawingRecorder. Text clips are initiated only in BoxPainter::paintLayerExtended, which is already
     // within a DrawingRecorder.
     OwnPtr<DrawingRecorder> drawingRecorder;
     if (RuntimeEnabledFeatures::slimmingPaintEnabled() && paintInfo.phase != PaintPhaseTextClip) {
         LayoutRect paintRect(m_inlineTextBox.logicalRectToPhysicalRect(logicalVisualOverflow));
         if (paintInfo.phase != PaintPhaseSelection && (haveSelection || containsComposition || paintsMarkerHighlights(m_inlineTextBox.layoutObject())))
             paintRect.unite(m_inlineTextBox.localSelectionRect(m_inlineTextBox.start(), m_inlineTextBox.start() + m_inlineTextBox.len()));
         paintRect.moveBy(adjustedPaintOffset);
@@ skipping 57 matching lines @@
 
     // 1. Paint backgrounds behind text if needed. Examples of such backgrounds include selection
     // and composition highlights.
     if (paintInfo.phase != PaintPhaseSelection && paintInfo.phase != PaintPhaseTextClip && !isPrinting) {
         if (containsComposition) {
             paintCompositionBackgrounds(context, boxOrigin, styleToUse, font, useCustomUnderlines);
         }
 
         paintDocumentMarkers(context, boxOrigin, styleToUse, font, true);
 
-        if (haveSelection && !useCustomUnderlines) {
+        if (haveSelection) {
             if (combinedText)
                 paintSelection<InlineTextBoxPainter::PaintOptions::CombinedText>(context, boxRect, styleToUse, font, selectionStyle.fillColor, combinedText);
             else
                 paintSelection<InlineTextBoxPainter::PaintOptions::Normal>(context, boxRect, styleToUse, font, selectionStyle.fillColor);
         }
     }
 
     // 2. Now paint the foreground, including text and decorations like underline/overline (in quirks mode only).
     int length = m_inlineTextBox.len();
     StringView string = m_inlineTextBox.layoutObject().text().createView();
@@ skipping 640 matching lines @@
             LayoutTheme::theme().platformActiveTextSearchHighlightColor() :
             LayoutTheme::theme().platformInactiveTextSearchHighlightColor();
         GraphicsContextStateSaver stateSaver(*pt);
         pt->clip(FloatRect(boxOrigin.x(), boxOrigin.y() - deltaY, m_inlineTextBox.logicalWidth(), selHeight));
         pt->drawHighlightForText(font, run, FloatPoint(boxOrigin.x(), boxOrigin.y() - deltaY), selHeight, color, sPos, ePos);
     }
 }
 
 
 } // namespace blink