diff --git a/PowerEditor/src/WinControls/DockingWnd/Gripper.cpp b/PowerEditor/src/WinControls/DockingWnd/Gripper.cpp
index 301c356ef..f8b07bf46 100644
--- a/PowerEditor/src/WinControls/DockingWnd/Gripper.cpp
+++ b/PowerEditor/src/WinControls/DockingWnd/Gripper.cpp
@@ -443,7 +443,7 @@ void Gripper::doTabReordering(POINT pt)
 			auto iSel = ::SendMessage(_hTab, TCM_GETCURSEL, 0, 0);
 			::SendMessage(_hTab, TCM_DELETEITEM, iSel, 0);
 		}
-		else if (_hTab == hTabOld)
+		else if (_hTab && _hTab == hTabOld)
 		{
 			// delete item on switch between tabs
 			::SendMessage(_hTab, TCM_DELETEITEM, iItemOld, 0);
diff --git a/PowerEditor/src/WinControls/FindCharsInRange/FindCharsInRange.cpp b/PowerEditor/src/WinControls/FindCharsInRange/FindCharsInRange.cpp
index 1c4f8fd47..fa32f488e 100644
--- a/PowerEditor/src/WinControls/FindCharsInRange/FindCharsInRange.cpp
+++ b/PowerEditor/src/WinControls/FindCharsInRange/FindCharsInRange.cpp
@@ -127,10 +127,10 @@ intptr_t CALLBACK FindCharsInRangeDlg::run_dlgProc(UINT message, WPARAM wParam,
 
 bool FindCharsInRangeDlg::findCharInRange(unsigned char beginRange, unsigned char endRange, intptr_t startPos, bool direction, bool wrap)
 {
-	size_t totalSize = (*_ppEditView)->getCurrentDocLen();
+	int64_t totalSize = (*_ppEditView)->getCurrentDocLen();
 	if (startPos == -1)
 		startPos = direction == dirDown ? 0 : totalSize - 1;
-	if (static_cast<size_t>(startPos) > totalSize)
+	if (startPos > totalSize)
 		return false;
 
 	char *content = new char[totalSize + 1];
@@ -139,8 +139,8 @@ bool FindCharsInRangeDlg::findCharInRange(unsigned char beginRange, unsigned cha
 	bool isFound = false;
 	size_t found = 0;
 
-	for (intptr_t i = startPos - (direction == dirUp ? 1 : 0); 
-		(direction == dirDown) ? i < static_cast<long long>(totalSize) : i >= 0 ;
+	for (int64_t i = startPos - (direction == dirDown ? 0 : 1);
+		(direction == dirDown) ? i < totalSize : i >= 0 ;
 		(direction == dirDown) ? (++i) : (--i))
 	{
 		if (static_cast<unsigned char>(content[i]) >= beginRange && static_cast<unsigned char>(content[i]) <= endRange)
@@ -155,7 +155,7 @@ bool FindCharsInRangeDlg::findCharInRange(unsigned char beginRange, unsigned cha
 	{
 		if (wrap)
 		{
-			for (size_t i = (direction == dirUp ? totalSize - 1 : 0); 
+			for (int64_t i = (direction == dirDown ? 0: totalSize - 1); 
 				(direction == dirDown) ? i < totalSize : i >= 0 ;
 				(direction == dirDown) ? (++i) : (--i))
 			{
diff --git a/PowerEditor/src/WinControls/ReadDirectoryChanges/ReadDirectoryChanges.cpp b/PowerEditor/src/WinControls/ReadDirectoryChanges/ReadDirectoryChanges.cpp
index bbbf053c7..c2433f2f8 100644
--- a/PowerEditor/src/WinControls/ReadDirectoryChanges/ReadDirectoryChanges.cpp
+++ b/PowerEditor/src/WinControls/ReadDirectoryChanges/ReadDirectoryChanges.cpp
@@ -82,6 +82,9 @@ void CReadDirectoryChanges::AddDirectory( LPCTSTR szDirectory, BOOL bWatchSubtre
 	if (!m_hThread)
 		Init();
 
+	if (!m_hThread)
+		return;
+
 	CReadChangesRequest* pRequest = new CReadChangesRequest(m_pServer, szDirectory, bWatchSubtree, dwNotifyFilter, dwBufferSize);
 	QueueUserAPC(CReadChangesServer::AddDirectoryProc, m_hThread, (ULONG_PTR)pRequest);
 }
diff --git a/PowerEditor/src/WinControls/WindowsDlg/WindowsDlg.cpp b/PowerEditor/src/WinControls/WindowsDlg/WindowsDlg.cpp
index 636e3d340..74111cb22 100644
--- a/PowerEditor/src/WinControls/WindowsDlg/WindowsDlg.cpp
+++ b/PowerEditor/src/WinControls/WindowsDlg/WindowsDlg.cpp
@@ -943,7 +943,10 @@ void WindowsDlg::doCount()
 
 void WindowsDlg::doSort()
 {
-	size_t count = (_pTab != NULL) ? _pTab->nbItem() : 0;	
+	if (_pTab == NULL)
+		return;
+
+	size_t count =  _pTab->nbItem();	
 	std::vector<UINT> items(count);
 	auto currrentTabIndex = _pTab->getCurrentTabIndex();
 	NMWINDLG nmdlg = {};
diff --git a/PowerEditor/visual.net/notepadPlus.ruleset b/PowerEditor/visual.net/notepadPlus.ruleset
index 2fde9ee3c..10cb35afa 100644
--- a/PowerEditor/visual.net/notepadPlus.ruleset
+++ b/PowerEditor/visual.net/notepadPlus.ruleset
@@ -38,7 +38,7 @@
     <Rule Id="C26433" Action="Hidden" />
     <Rule Id="C26434" Action="Hidden" />
     <Rule Id="C26435" Action="Warning" />
-    <Rule Id="C26436" Action="Warning" />
+    <Rule Id="C26436" Action="Hidden" />  <!-- The type 'symbol' with a virtual function needs either public virtual or protected non-virtual destructor -->
     <Rule Id="C26437" Action="Warning" />
     <Rule Id="C26438" Action="Error" />   <!-- Avoid goto -->
     <Rule Id="C26439" Action="Warning" />
@@ -71,7 +71,7 @@
     <Rule Id="C26473" Action="Warning" />
     <Rule Id="C26474" Action="Hidden" />  <!-- Don't cast between pointer types when the conversion could be implicit. -->
     <Rule Id="C26475" Action="Hidden" />  <!-- Do not use function style C-casts. -->
-    <Rule Id="C26476" Action="Warning" />
+    <Rule Id="C26476" Action="Hidden" />  <!-- Expression/symbol 'name' uses a naked union 'union' with multiple type pointers: Use variant instead -->
     <Rule Id="C26477" Action="Hidden" />  <!-- Use 'nullptr' rather than 0 or NULL  -->
     <Rule Id="C26478" Action="Warning" />
     <Rule Id="C26479" Action="Warning" />
@@ -205,7 +205,7 @@
     <Rule Id="C33011" Action="Warning" />
     <Rule Id="C33020" Action="Warning" />
     <Rule Id="C6001" Action="Warning" />
-    <Rule Id="C6011" Action="Warning" />
+    <Rule Id="C6011" Action="Error" />    <!-- Dereferencing NULL pointer 'pointer-name'. -->
     <Rule Id="C6029" Action="Warning" />
     <Rule Id="C6031" Action="None" />
     <Rule Id="C6053" Action="Warning" />
@@ -255,7 +255,7 @@
     <Rule Id="C6284" Action="Warning" />
     <Rule Id="C6285" Action="Warning" />
     <Rule Id="C6286" Action="Warning" />
-    <Rule Id="C6287" Action="Warning" />
+    <Rule Id="C6287" Action="Hidden" />  <!-- Redundant code: the left and right subexpressions are identical -->
     <Rule Id="C6288" Action="Warning" />
     <Rule Id="C6289" Action="Warning" />
     <Rule Id="C6290" Action="Warning" />