diff --git a/libs/text/KoTextBlockData.cpp b/libs/text/KoTextBlockData.cpp
--- a/libs/text/KoTextBlockData.cpp
+++ b/libs/text/KoTextBlockData.cpp
@@ -81,7 +81,15 @@
 
 void KoTextBlockData::appendMarkup(MarkupType type, int firstChar, int lastChar)
 {
-    Q_ASSERT(d->markupRangesMap[type].isEmpty() || d->markupRangesMap[type].last().lastChar < firstChar);
+    if (type == KoTextBlockData::Grammar) {
+        Q_ASSERT(d->markupRangesMap[type].isEmpty() || d->markupRangesMap[type].last().lastChar < firstChar);
+    } else if (!d->markupRangesMap[type].isEmpty() && d->markupRangesMap[type].last().lastChar >= firstChar) {
+        // Character positions from spellchecker are not in sync with document.
+        // I have only seen this in connection with dropcaps, so could be caused by
+        // large amount to spellcheck combined with large changes to the document.
+        // Anyway, returning here just means markup will be incorrect/missing until next spellcheck is run.
+        return;
+    }
 
     MarkupRange range;
     range.firstChar = firstChar;
diff --git a/plugins/textediting/spellcheck/SpellCheck.h b/plugins/textediting/spellcheck/SpellCheck.h
--- a/plugins/textediting/spellcheck/SpellCheck.h
+++ b/plugins/textediting/spellcheck/SpellCheck.h
@@ -86,7 +86,7 @@
     void configureSpellCheck();
     void runQueue();
     void setBackgroundSpellChecking(bool b);
-    void documentChanged(int from, int min, int plus);
+    void documentChanged(int from, int charsRemoved, int charsAdded);
 
 private:
     Sonnet::Speller m_speller;
@@ -111,7 +111,8 @@
     QTextStream stream;
     SpellCheckMenu *m_spellCheckMenu;
     SpellSections m_activeSection; // the section we are currently doing a run on;
-    bool m_simpleEdit; //set when user is doing a simple edit, meaning we should ignore documentCanged
+    bool m_simpleEdit; //set when user is doing a simple edit, meaning we should not start spellchecking
+    int m_cursorPosition; // simple edit cursor position
 };
 
 #endif
diff --git a/plugins/textediting/spellcheck/SpellCheck.cpp b/plugins/textediting/spellcheck/SpellCheck.cpp
--- a/plugins/textediting/spellcheck/SpellCheck.cpp
+++ b/plugins/textediting/spellcheck/SpellCheck.cpp
@@ -52,6 +52,7 @@
     , m_spellCheckMenu(0)
     , m_activeSection(0, 0, 0)
     , m_simpleEdit(false)
+    , m_cursorPosition(0)
 {
     /* setup actions for this plugin */
     QAction *configureAction = new QAction(i18n("Configure &Spell Checking..."), this);
@@ -102,8 +103,7 @@
 {
     m_simpleEdit = true;
     setDocument(document);
-    Q_UNUSED(document);
-    Q_UNUSED(cursorPosition);
+    m_cursorPosition = cursorPosition;
 }
 
 void SpellCheck::checkSection(QTextDocument *document, int startPosition, int endPosition)
@@ -241,8 +241,9 @@
     blockData.appendMarkup(KoTextBlockData::Misspell, startPosition - block.position(), startPosition - block.position() + word.trimmed().length());
 }
 
-void SpellCheck::documentChanged(int from, int min, int plus)
+void SpellCheck::documentChanged(int from, int charsRemoved, int charsAdded)
 {
+    Q_UNUSED(charsRemoved);
     QTextDocument *document = qobject_cast<QTextDocument*>(sender());
     if (document == 0)
         return;
@@ -255,17 +256,21 @@
         KoTextBlockData blockData(block);
         if (m_enableSpellCheck) {
             blockData.setMarkupsLayoutValidity(KoTextBlockData::Misspell, false);
-            if (m_simpleEdit) {
-                // if it's a simple edit we will wait until finishedWord
-                blockData.rebaseMarkups(KoTextBlockData::Misspell, from, plus - min);
+            // We cannot safely handle combined remove/add in case it spans words.
+            // This should probably never be defined as a simple edit anyway,
+            // but atm lines with dropcaps trigger this behaviour. See KoTextLayoutArea.
+            if (m_simpleEdit && (charsRemoved == 0 || charsAdded == 0)) {
+                // If it's a simple edit we will wait until finishedWord before spellchecking
+                // but we need to adjust all markups behind the added/removed character(s)
+                blockData.rebaseMarkups(KoTextBlockData::Misspell, from - block.position(), charsAdded - charsRemoved);
             } else {
                 checkSection(document, block.position(), block.position() + block.length() - 1);
             }
         } else {
             blockData.clearMarkups(KoTextBlockData::Misspell);
         }
         block = block.next();
-    } while(block.isValid() && block.position() <= from + plus);
+    } while(block.isValid() && block.position() <= from + charsAdded);
 
     m_simpleEdit = false;
 }