diff --git a/libs/image/kis_simple_update_queue.cpp b/libs/image/kis_simple_update_queue.cpp
index 03078df8e8..2e2d6bde13 100644
--- a/libs/image/kis_simple_update_queue.cpp
+++ b/libs/image/kis_simple_update_queue.cpp
@@ -1,407 +1,407 @@
 /*
  *  Copyright (c) 2010 Dmitry Kazakov <dimula73@gmail.com>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
 #include "kis_simple_update_queue.h"
 
 #include <QMutexLocker>
 #include <QVector>
 
 #include "kis_image_config.h"
 #include "kis_full_refresh_walker.h"
 #include "kis_spontaneous_job.h"
 
 
 //#define ENABLE_DEBUG_JOIN
 //#define ENABLE_ACCUMULATOR
 
 #ifdef ENABLE_DEBUG_JOIN
     #define DEBUG_JOIN(baseRect, newRect, alpha)                     \
         dbgKrita << "Two rects were joined:\t"                       \
                  << (baseRect) << "+" << (newRect) << "->"           \
                  << ((baseRect) | (newRect)) << "(" << alpha << ")"
 
 #else
     #define DEBUG_JOIN(baseRect, newRect, alpha)
 #endif /* ENABLE_DEBUG_JOIN */
 
 
 #ifdef ENABLE_ACCUMULATOR
     #define DECLARE_ACCUMULATOR() static qreal _baseAmount=0, _newAmount=0
     #define ACCUMULATOR_ADD(baseAmount, newAmount) \
         do {_baseAmount += baseAmount; _newAmount += newAmount;} while (0)
     #define ACCUMULATOR_DEBUG() \
         dbgKrita << "Accumulated alpha:" << _newAmount / _baseAmount
 #else
     #define DECLARE_ACCUMULATOR()
     #define ACCUMULATOR_ADD(baseAmount, newAmount)
     #define ACCUMULATOR_DEBUG()
 #endif /* ENABLE_ACCUMULATOR */
 
 
 KisSimpleUpdateQueue::KisSimpleUpdateQueue()
     : m_overrideLevelOfDetail(-1)
 {
     updateSettings();
 }
 
 KisSimpleUpdateQueue::~KisSimpleUpdateQueue()
 {
     QWriteLocker locker(&m_rwLock);
 
     while (!m_spontaneousJobsList.isEmpty()) {
         delete m_spontaneousJobsList.takeLast();
     }
 }
 
 void KisSimpleUpdateQueue::updateSettings()
 {
     QWriteLocker locker(&m_rwLock);
 
     KisImageConfig config(true);
 
     m_patchWidth = config.updatePatchWidth();
     m_patchHeight = config.updatePatchHeight();
 
     m_maxCollectAlpha = config.maxCollectAlpha();
     m_maxMergeAlpha = config.maxMergeAlpha();
     m_maxMergeCollectAlpha = config.maxMergeCollectAlpha();
 }
 
 int KisSimpleUpdateQueue::overrideLevelOfDetail() const
 {
     return m_overrideLevelOfDetail;
 }
 
 void KisSimpleUpdateQueue::processQueue(KisUpdaterContext &updaterContext)
 {
     updaterContext.lock();
     m_rwLock.lockForWrite();
 
     while(updaterContext.hasSpareThread() &&
           processOneJob(updaterContext));
 
     m_rwLock.unlock();
     updaterContext.unlock();
 }
 
 bool KisSimpleUpdateQueue::processOneJob(KisUpdaterContext &updaterContext)
 {
     KisBaseRectsWalkerSP item;
     KisMutableWalkersListIterator iter(m_updatesList);
-    QVector<KisBaseRectsWalkerSP> walkers;
+//    QVector<KisBaseRectsWalkerSP> walkers;
     bool jobAdded = false;
 
     int currentLevelOfDetail = updaterContext.currentLevelOfDetail();
 
     while(iter.hasNext()) {
         item = iter.next();
 
         if ((currentLevelOfDetail < 0 || currentLevelOfDetail == item->levelOfDetail()) &&
             !item->checksumValid()) {
 
             m_overrideLevelOfDetail = item->levelOfDetail();
             item->recalculate(item->requestedRect());
             m_overrideLevelOfDetail = -1;
         }
 
         if ((currentLevelOfDetail < 0 || currentLevelOfDetail == item->levelOfDetail()) &&
             updaterContext.isJobAllowed(item)) {
-            walkers.append(item);
-//            while (!updaterContext.addMergeJob(item));
+//            walkers.append(item);
+            while (!updaterContext.addMergeJob(item));
 
             iter.remove();
 
-//            jobAdded = true;
-//            break;
+            jobAdded = true;
+            break;
         }
     }
 
-    if (!walkers.isEmpty()) {
-        while (!updaterContext.addMergeJobs(walkers));
-        jobAdded = true;
-    }
+//    if (!walkers.isEmpty()) {
+//        while (!updaterContext.addMergeJobs(walkers));
+//        jobAdded = true;
+//    }
 
     if (jobAdded) return true;
 
     if (!m_spontaneousJobsList.isEmpty()) {
         /**
          * WARNING: Please note that this still doesn't guarantee that
          * the spontaneous jobs are exclusive, since updates and/or
          * strokes can be added after them. The only thing it
          * guarantees that two spontaneous jobs will not be executed
          * in parallel.
          *
          * Right now it works as it is. Probably will need to be fixed
          * in the future.
          */
         qint32 numMergeJobs;
         qint32 numStrokeJobs;
         updaterContext.getJobsSnapshot(numMergeJobs, numStrokeJobs);
 
         if (!numMergeJobs && !numStrokeJobs) {
             KisSpontaneousJob *job = m_spontaneousJobsList.takeFirst();
             while (!updaterContext.addSpontaneousJob(job));
             jobAdded = true;
         }
     }
 
     return jobAdded;
 }
 
 void KisSimpleUpdateQueue::addUpdateJob(KisNodeSP node, const QVector<QRect> &rects, const QRect& cropRect, int levelOfDetail)
 {
     addJob(node, rects, cropRect, levelOfDetail, KisBaseRectsWalker::UPDATE);
 }
 
 void KisSimpleUpdateQueue::addUpdateJob(KisNodeSP node, const QRect &rc, const QRect& cropRect, int levelOfDetail)
 {
     addJob(node, {rc}, cropRect, levelOfDetail, KisBaseRectsWalker::UPDATE);
 }
 
 
 void KisSimpleUpdateQueue::addUpdateNoFilthyJob(KisNodeSP node, const QRect& rc, const QRect& cropRect, int levelOfDetail)
 {
     addJob(node, {rc}, cropRect, levelOfDetail, KisBaseRectsWalker::UPDATE_NO_FILTHY);
 }
 
 void KisSimpleUpdateQueue::addFullRefreshJob(KisNodeSP node, const QRect& rc, const QRect& cropRect, int levelOfDetail)
 {
     addJob(node, {rc}, cropRect, levelOfDetail, KisBaseRectsWalker::FULL_REFRESH);
 }
 
 void KisSimpleUpdateQueue::addJob(KisNodeSP node, const QVector<QRect> &rects,
                                   const QRect& cropRect,
                                   int levelOfDetail,
                                   KisBaseRectsWalker::UpdateType type)
 {
     QList<KisBaseRectsWalkerSP> walkers;
 
     Q_FOREACH (const QRect &rc, rects) {
         if (rc.isEmpty()) continue;
 
         KisBaseRectsWalkerSP walker;
 
         if(trySplitJob(node, rc, cropRect, levelOfDetail, type)) continue;
         if(tryMergeJob(node, rc, cropRect, levelOfDetail, type)) continue;
 
         if (type == KisBaseRectsWalker::UPDATE) {
             walker = new KisMergeWalker(cropRect, KisMergeWalker::DEFAULT);
         }
         else if (type == KisBaseRectsWalker::FULL_REFRESH)  {
             walker = new KisFullRefreshWalker(cropRect);
         }
         else if (type == KisBaseRectsWalker::UPDATE_NO_FILTHY) {
             walker = new KisMergeWalker(cropRect, KisMergeWalker::NO_FILTHY);
         }
         /* else if(type == KisBaseRectsWalker::UNSUPPORTED) fatalKrita; */
 
         walker->collectRects(node, rc);
         walkers.append(walker);
     }
 
     if (!walkers.isEmpty()) {
         m_rwLock.lockForWrite();
         m_updatesList.append(walkers);
         m_rwLock.unlock();
     }
 }
 
 void KisSimpleUpdateQueue::addSpontaneousJob(KisSpontaneousJob *spontaneousJob)
 {
     QWriteLocker locker(&m_rwLock);
 
     KisSpontaneousJob *item;
     KisMutableSpontaneousJobsListIterator iter(m_spontaneousJobsList);
 
     iter.toBack();
 
     while(iter.hasPrevious()) {
         item = iter.previous();
 
         if (spontaneousJob->overrides(item)) {
             iter.remove();
             delete item;
         }
     }
 
     m_spontaneousJobsList.append(spontaneousJob);
 }
 
 bool KisSimpleUpdateQueue::isEmpty() const
 {
 //    QReadLocker locker(&m_rwLock);
     return m_updatesList.isEmpty() && m_spontaneousJobsList.isEmpty();
 }
 
 qint32 KisSimpleUpdateQueue::sizeMetric() const
 {
 //    QReadLocker locker(&m_rwLock);
     return m_updatesList.size() + m_spontaneousJobsList.size();
 }
 
 bool KisSimpleUpdateQueue::trySplitJob(KisNodeSP node, const QRect& rc,
                                        const QRect& cropRect,
                                        int levelOfDetail,
                                        KisBaseRectsWalker::UpdateType type)
 {
     if(rc.width() <= m_patchWidth || rc.height() <= m_patchHeight)
         return false;
 
     // a bit of recursive splitting...
 
     qint32 firstCol = rc.x() / m_patchWidth;
     qint32 firstRow = rc.y() / m_patchHeight;
 
     qint32 lastCol = (rc.x() + rc.width()) / m_patchWidth;
     qint32 lastRow = (rc.y() + rc.height()) / m_patchHeight;
 
     QVector<QRect> splitRects;
 
     for(qint32 i = firstRow; i <= lastRow; i++) {
         for(qint32 j = firstCol; j <= lastCol; j++) {
             QRect maxPatchRect(j * m_patchWidth, i * m_patchHeight,
                                m_patchWidth, m_patchHeight);
             QRect patchRect = rc & maxPatchRect;
             splitRects.append(patchRect);
         }
     }
 
     KIS_SAFE_ASSERT_RECOVER_NOOP(!splitRects.isEmpty());
     addJob(node, splitRects, cropRect, levelOfDetail, type);
 
     return true;
 }
 
 bool KisSimpleUpdateQueue::tryMergeJob(KisNodeSP node, const QRect& rc,
                                        const QRect& cropRect,
                                        int levelOfDetail,
                                        KisBaseRectsWalker::UpdateType type)
 {
     QWriteLocker locker(&m_rwLock);
 
     QRect baseRect = rc;
 
     KisBaseRectsWalkerSP goodCandidate;
     KisBaseRectsWalkerSP item;
     KisWalkersListIterator iter(m_updatesList);
 
     /**
      * We add new jobs to the tail of the list,
      * so it's more probable to find a good candidate here.
      */
 
     iter.toBack();
 
     while(iter.hasPrevious()) {
         item = iter.previous();
 
         if(item->startNode() != node) continue;
         if(item->type() != type) continue;
         if(item->cropRect() != cropRect) continue;
         if(item->levelOfDetail() != levelOfDetail) continue;
 
         if(joinRects(baseRect, item->requestedRect(), m_maxMergeAlpha)) {
             goodCandidate = item;
             break;
         }
     }
 
     if(goodCandidate)
         collectJobs(goodCandidate, baseRect, m_maxMergeCollectAlpha);
 
     return (bool)goodCandidate;
 }
 
 void KisSimpleUpdateQueue::optimize()
 {
     QWriteLocker locker(&m_rwLock);
 
     if(m_updatesList.size() <= 1) {
         return;
     }
 
     KisBaseRectsWalkerSP baseWalker = m_updatesList.first();
     QRect baseRect = baseWalker->requestedRect();
 
     collectJobs(baseWalker, baseRect, m_maxCollectAlpha);
 }
 
 void KisSimpleUpdateQueue::collectJobs(KisBaseRectsWalkerSP &baseWalker,
                                        QRect baseRect,
                                        const qreal maxAlpha)
 {
     KisBaseRectsWalkerSP item;
     KisMutableWalkersListIterator iter(m_updatesList);
 
     while(iter.hasNext()) {
         item = iter.next();
 
         if(item == baseWalker) continue;
         if(item->type() != baseWalker->type()) continue;
         if(item->startNode() != baseWalker->startNode()) continue;
         if(item->cropRect() != baseWalker->cropRect()) continue;
         if(item->levelOfDetail() != baseWalker->levelOfDetail()) continue;
 
         if(joinRects(baseRect, item->requestedRect(), maxAlpha)) {
             iter.remove();
         }
     }
 
     if(baseWalker->requestedRect() != baseRect) {
         baseWalker->collectRects(baseWalker->startNode(), baseRect);
     }
 }
 
 bool KisSimpleUpdateQueue::joinRects(QRect& baseRect,
                                      const QRect& newRect, qreal maxAlpha)
 {
     QRect unitedRect = baseRect | newRect;
     if(unitedRect.width() > m_patchWidth || unitedRect.height() > m_patchHeight)
         return false;
 
     bool result = false;
     qint64 baseWork = baseRect.width() * baseRect.height() +
         newRect.width() * newRect.height();
 
     qint64 newWork = unitedRect.width() * unitedRect.height();
 
     qreal alpha = qreal(newWork) / baseWork;
 
     if(alpha < maxAlpha) {
         DEBUG_JOIN(baseRect, newRect, alpha);
 
         DECLARE_ACCUMULATOR();
         ACCUMULATOR_ADD(baseWork, newWork);
         ACCUMULATOR_DEBUG();
 
         baseRect = unitedRect;
         result = true;
     }
 
     return result;
 }
 
 KisWalkersList& KisTestableSimpleUpdateQueue::getWalkersList()
 {
     return m_updatesList;
 }
 
 KisSpontaneousJobsList& KisTestableSimpleUpdateQueue::getSpontaneousJobsList()
 {
     return m_spontaneousJobsList;
 }