--- a/widget/ContentCache.cpp
+++ b/widget/ContentCache.cpp
@@ -505,16 +505,17 @@ ContentCacheInChild::SetSelection(nsIWid
 /*****************************************************************************
  * mozilla::ContentCacheInParent
  *****************************************************************************/
 
 ContentCacheInParent::ContentCacheInParent()
   : ContentCache()
   , mCommitStringByRequest(nullptr)
   , mPendingEventsNeedingAck(0)
+  , mCompositionStartInChild(UINT32_MAX)
   , mPendingCompositionCount(0)
   , mWidgetHasComposition(false)
 {
 }
 
 void
 ContentCacheInParent::AssignContent(const ContentCache& aOther,
                                     nsIWidget* aWidget,
@@ -534,16 +535,17 @@ ContentCacheInParent::AssignContent(cons
   if (mWidgetHasComposition && mPendingCompositionCount == 1) {
     IMEStateManager::MaybeStartOffsetUpdatedInChild(aWidget, mCompositionStart);
   }
 
   // When the widget has composition, we should set mCompositionStart to
   // *current* composition start offset.  Note that, in strictly speaking,
   // widget should not use WidgetQueryContentEvent if there are some pending
   // compositions (i.e., when mPendingCompositionCount is 2 or more).
+  mCompositionStartInChild = aOther.mCompositionStart;
   if (mWidgetHasComposition) {
     if (aOther.mCompositionStart != UINT32_MAX) {
       mCompositionStart = aOther.mCompositionStart;
     } else {
       mCompositionStart = mSelection.StartOffset();
       NS_WARNING_ASSERTION(mCompositionStart != UINT32_MAX,
                            "mCompositionStart shouldn't be invalid offset when "
                            "the widget has composition");
@@ -1086,16 +1088,22 @@ ContentCacheInParent::OnCompositionEvent
      mCommitStringByRequest));
 
   // We must be able to simulate the selection because
   // we might not receive selection updates in time
   if (!mWidgetHasComposition) {
     if (aEvent.mWidget && aEvent.mWidget->PluginHasFocus()) {
       // If focus is on plugin, we cannot get selection range
       mCompositionStart = 0;
+    } else if (mCompositionStartInChild != UINT32_MAX) {
+      // If there is pending composition in the remote process, let's use
+      // its start offset temporarily because this stores a lot of information
+      // around it and the user must look around there, so, showing some UI
+      // around it must make sense.
+      mCompositionStart = mCompositionStartInChild;
     } else {
       mCompositionStart = mSelection.StartOffset();
     }
     MOZ_ASSERT(aEvent.mMessage == eCompositionStart);
     MOZ_RELEASE_ASSERT(mPendingCompositionCount < UINT8_MAX);
     mPendingCompositionCount++;
   }
 

--- a/widget/ContentCache.h
+++ b/widget/ContentCache.h
@@ -409,16 +409,19 @@ private:
   // This is not nullptr only while the instance is requesting IME to
   // composition.  Then, data value of dispatched composition events should
   // be stored into the instance.
   nsAString* mCommitStringByRequest;
   // mPendingEventsNeedingAck is increased before sending a composition event or
   // a selection event and decreased after they are received in the child
   // process.
   uint32_t mPendingEventsNeedingAck;
+  // mCompositionStartInChild stores current composition start offset in the
+  // remote process.
+  uint32_t mCompositionStartInChild;
   // mPendingCompositionCount is number of compositions which started in widget
   // but not yet handled in the child process.
   uint8_t mPendingCompositionCount;
   // mWidgetHasComposition is true when the widget in this process thinks that
   // IME has composition.  So, this is set to true when eCompositionStart is
   // dispatched and set to false when eCompositionCommit(AsIs) is dispatched.
   bool mWidgetHasComposition;