diff --git a/application/dashboard.class.inc.php b/application/dashboard.class.inc.php
index 764143fb7..5828a80f2 100644
--- a/application/dashboard.class.inc.php
+++ b/application/dashboard.class.inc.php
@@ -710,9 +710,9 @@ class RuntimeDashboard extends Dashboard
 	 */
 	public function Render($oPage, $bEditMode = false, $aExtraParams = array())
 	{
-		if (!isset($aExtraParams['query_params']) && isset($aExtraParams['class']))
+		if (!isset($aExtraParams['query_params']) && isset($aExtraParams['this->class']))
 		{
-			$oObj = MetaModel::GetObject($aExtraParams['class'], $aExtraParams['id']);
+			$oObj = MetaModel::GetObject($aExtraParams['this->class'], $aExtraParams['this->id']);
 			$aRenderParams = array('query_params' => $oObj->ToArgsForQuery());
 		}
 		else
@@ -726,7 +726,7 @@ class RuntimeDashboard extends Dashboard
 		{
 			/** @var \DBObject $oObj */
 			$oObj = $aExtraParams['query_params']['this->object()'];
-			$aAjaxParams = array('class' => get_class($oObj), 'id' => $oObj->GetKey());
+			$aAjaxParams = array('this->class' => get_class($oObj), 'this->id' => $oObj->GetKey());
 		}
 		else
 		{
@@ -938,9 +938,9 @@ EOF
 	 */
 	public function RenderEditor($oPage, $aExtraParams = array())
 	{
-		if (isset($aExtraParams['class']))
+		if (isset($aExtraParams['this->class']))
 		{
-			$oObj = MetaModel::GetObject($aExtraParams['class'], $aExtraParams['id']);
+			$oObj = MetaModel::GetObject($aExtraParams['this->class'], $aExtraParams['this->id']);
 			$aRenderParams = array('query_params' => $oObj->ToArgsForQuery());
 		}
 		else
diff --git a/application/dashlet.class.inc.php b/application/dashlet.class.inc.php
index d98be77aa..a1672ee21 100644
--- a/application/dashlet.class.inc.php
+++ b/application/dashlet.class.inc.php
@@ -781,9 +781,9 @@ class DashletObjectList extends Dashlet
 		{
 			$aQueryParams = $aExtraParams['query_params'];
 		}
-		elseif (isset($aExtraParams['class']))
+		elseif (isset($aExtraParams['this->class']))
 		{
-			$oObj = MetaModel::GetObject($aExtraParams['class'], $aExtraParams['id']);
+			$oObj = MetaModel::GetObject($aExtraParams['this->class'], $aExtraParams['this->id']);
 			$aQueryParams = $oObj->ToArgsForQuery();
 		}
 		else
@@ -1020,6 +1020,8 @@ abstract class DashletGroupBy extends Dashlet
 	 * @param bool $bEditMode
 	 * @param array $aExtraParams
 	 *
+	 * @throws \ArchivedObjectException
+	 * @throws \CoreException
 	 * @throws \OQLException
 	 */
 	public function Render($oPage, $bEditMode = false, $aExtraParams = array())
@@ -1033,9 +1035,9 @@ abstract class DashletGroupBy extends Dashlet
 		{
 			$aQueryParams = $aExtraParams['query_params'];
 		}
-		elseif (isset($aExtraParams['class']))
+		elseif (isset($aExtraParams['this->class']))
 		{
-			$oObj = MetaModel::GetObject($aExtraParams['class'], $aExtraParams['id']);
+			$oObj = MetaModel::GetObject($aExtraParams['this->class'], $aExtraParams['this->id']);
 			$aQueryParams = $oObj->ToArgsForQuery();
 		}
 		else
@@ -1837,9 +1839,9 @@ class DashletHeaderDynamic extends Dashlet
 		{
 			$aQueryParams = $aExtraParams['query_params'];
 		}
-		elseif (isset($aExtraParams['class']))
+		elseif (isset($aExtraParams['this->class']))
 		{
-			$oObj = MetaModel::GetObject($aExtraParams['class'], $aExtraParams['id']);
+			$oObj = MetaModel::GetObject($aExtraParams['this->class'], $aExtraParams['this->id']);
 			$aQueryParams = $oObj->ToArgsForQuery();
 		}
 		else
diff --git a/application/displayblock.class.inc.php b/application/displayblock.class.inc.php
index 48a68c62d..ff670f5b2 100644
--- a/application/displayblock.class.inc.php
+++ b/application/displayblock.class.inc.php
@@ -472,7 +472,7 @@ class DisplayBlock
 					{
 						$aQueryParams = array();
 					}
-					$sFilter = urlencode($oSubsetSearch->serialize(false, $aQueryParams));
+					$sFilter = $oSubsetSearch->serialize(false, $aQueryParams);
 
 					$aData[] = array ('group' => $aLabels[$iRow],
 									  'value' => "<a href=\"".utils::GetAbsoluteUrlAppRoot()."pages/UI.php?operation=search&dosearch=1&$sParams&filter=$sFilter\">$iCount</a>"); // TO DO: add the context information
@@ -749,7 +749,7 @@ class DisplayBlock
 				$this->m_oSet->SetShowObsoleteData($this->m_bShowObsoleteData);
 			}
 			$iCount = $this->m_oSet->Count();
-			$sHyperlink = utils::GetAbsoluteUrlAppRoot().'pages/UI.php?operation=search&'.$oAppContext->GetForLink().'&filter='.urlencode($this->m_oFilter->serialize());
+			$sHyperlink = utils::GetAbsoluteUrlAppRoot().'pages/UI.php?operation=search&'.$oAppContext->GetForLink().'&filter='.$this->m_oFilter->serialize();
 			$sHtml .= '<p><a class="actions" href="'.$sHyperlink.'">';
 			// Note: border set to 0 due to various browser interpretations (IE9 adding a 2px border)
 			$sHtml .= MetaModel::GetClassIcon($sClass, true, 'float;left;margin-right:10px;border:0;');
@@ -838,7 +838,7 @@ class DisplayBlock
 						}
 						$sHyperlink = utils::GetAbsoluteUrlAppRoot()
 							.'pages/UI.php?operation=search&'.$oAppContext->GetForLink()
-							.'&filter='.urlencode($oSingleGroupByValueFilter->serialize());
+							.'&filter='.$oSingleGroupByValueFilter->serialize();
 						$aCounts[$sStateValue] = "<a href=\"$sHyperlink\">{$aCounts[$sStateValue]}</a>";
 					}
 				}
@@ -847,7 +847,7 @@ class DisplayBlock
 			$sHtml .= '<tr><td>'.implode('</td><td>', $aCounts).'</td></tr></table></div>';
 			// Title & summary
 			$iCount = $this->m_oSet->Count();
-			$sHyperlink = utils::GetAbsoluteUrlAppRoot().'pages/UI.php?operation=search&'.$oAppContext->GetForLink().'&filter='.urlencode($this->m_oFilter->serialize());
+			$sHyperlink = utils::GetAbsoluteUrlAppRoot().'pages/UI.php?operation=search&'.$oAppContext->GetForLink().'&filter='.$this->m_oFilter->serialize();
 			$sHtml .= '<h1>'.Dict::S(str_replace('_', ':', $sTitle)).'</h1>';
 			$sHtml .= '<a class="summary" href="'.$sHyperlink.'">'.Dict::Format(str_replace('_', ':', $sLabel), $iCount).'</a>';
 			$sHtml .= '<div style="clear:both;"></div>';
@@ -858,7 +858,7 @@ class DisplayBlock
 
 			$sCsvFile = strtolower($this->m_oFilter->GetClass()).'.csv'; 
 			$sDownloadLink = utils::GetAbsoluteUrlAppRoot().'webservices/export.php?expression='.urlencode($this->m_oFilter->ToOQL(true)).'&format=csv&filename='.urlencode($sCsvFile);
-			$sLinkToToggle = utils::GetAbsoluteUrlAppRoot().'pages/UI.php?operation=search&'.$oAppContext->GetForLink().'&filter='.urlencode($this->m_oFilter->serialize()).'&format=csv';
+			$sLinkToToggle = utils::GetAbsoluteUrlAppRoot().'pages/UI.php?operation=search&'.$oAppContext->GetForLink().'&filter='.$this->m_oFilter->serialize().'&format=csv';
 			// Pass the parameters via POST, since expression may be very long
 			$aParamsToPost = array(
 				'expression' => $this->m_oFilter->ToOQL(true),
@@ -986,7 +986,7 @@ EOF
 					$oSubsetSearch = $this->m_oFilter->DeepClone();
 					$oCondition = new BinaryExpression($oGroupByExp, '=', new ScalarExpression($sValue));
 					$oSubsetSearch->AddConditionExpression($oCondition);
-					$aURLs[] = utils::GetAbsoluteUrlAppRoot()."pages/UI.php?operation=search&format=html&filter=".urlencode($oSubsetSearch->serialize()).'&'.$sContextParam;
+					$aURLs[] = utils::GetAbsoluteUrlAppRoot()."pages/UI.php?operation=search&format=html&filter=".$oSubsetSearch->serialize().'&'.$sContextParam;
 				}
 				$sJSURLs = json_encode($aURLs);
 			}
diff --git a/application/ui.extkeywidget.class.inc.php b/application/ui.extkeywidget.class.inc.php
index 780ed999c..6978a7cb4 100644
--- a/application/ui.extkeywidget.class.inc.php
+++ b/application/ui.extkeywidget.class.inc.php
@@ -332,7 +332,8 @@ EOF
 		if ( ($oCurrObject != null) && ($this->sAttCode != ''))
 		{
 			$oAttDef = MetaModel::GetAttributeDef(get_class($oCurrObject), $this->sAttCode);
-			$aArgs = array('this' => $oCurrObject);
+			/** @var \DBObject $oCurrObject */
+			$aArgs = $oCurrObject->ToArgsForQuery();
 			$aParams = array('query_params' => $aArgs);
 			$oSet = $oAttDef->GetAllowedValuesAsObjectSet($aArgs);
 			$oFilter = $oSet->GetFilter();
diff --git a/core/attributedef.class.inc.php b/core/attributedef.class.inc.php
index 0de09da88..113680a03 100644
--- a/core/attributedef.class.inc.php
+++ b/core/attributedef.class.inc.php
@@ -9939,7 +9939,7 @@ class AttributeTagSet extends AttributeSet
 				$oAppContext = new ApplicationContext();
 				$sContext = $oAppContext->GetForLink();
 				$sUIPage = cmdbAbstractObject::ComputeStandardUIPage($oFilter->GetClass());
-				$sFilter = urlencode($oFilter->serialize());
+				$sFilter = $oFilter->serialize();
 				$sUrl = utils::GetAbsoluteUrlAppRoot()."pages/$sUIPage?operation=search&filter=".$sFilter."&{$sContext}";
 
 				$sHtml .= '<a href="'.$sUrl.'" class="attribute-set-item attribute-set-item-'.$sTagCode.'" data-code="'.$sTagCode.'" data-label="'.htmlentities($sTagLabel, ENT_QUOTES, 'UTF-8').'" data-description="'.htmlentities($sTagDescription, ENT_QUOTES, 'UTF-8').'">'.$sTagLabel.'</a>';
diff --git a/core/dbsearch.class.php b/core/dbsearch.class.php
index 81533993a..0da1efbce 100644
--- a/core/dbsearch.class.php
+++ b/core/dbsearch.class.php
@@ -262,34 +262,63 @@ abstract class DBSearch
 				if (isset($aContextParams[$sParamName.'->object()']))
 				{
 					$sAttCode = substr($sParam, $iPos + 2);
+					/** @var \DBObject $oObj */
 					$oObj = $aContextParams[$sParamName.'->object()'];
-					if ($sAttCode == 'id')
+					if ($oObj->IsModified())
 					{
-						$aQueryParams[$sParam] = $oObj->GetKey();
+						if ($sAttCode == 'id')
+						{
+							$aQueryParams[$sParam] = $oObj->GetKey();
+						}
+						else
+						{
+							$aQueryParams[$sParam] = $oObj->Get($sAttCode);
+						}
 					}
 					else
 					{
-						$aQueryParams[$sParam] = $oObj->Get($sAttCode);
+						unset($aQueryParams[$sParam]);
+						// For database objects, serialize only class, key
+						$aQueryParams[$sParamName.'->id'] = $oObj->GetKey();
+						$aQueryParams[$sParamName.'->class'] = get_class($oObj);
 					}
 				}
 			}
 		}
 
 		$sOql = $this->ToOql($bDevelopParams, $aContextParams);
-		return rawurlencode(base64_encode(serialize(array($sOql, $aQueryParams, $this->m_aModifierProperties))));
+		return rawurlencode(json_encode(array($sOql, $aQueryParams, $this->m_aModifierProperties)));
 	}
 
 	/**
 	 * @param string $sValue Serialized OQL query
 	 *
 	 * @return \DBSearch
+	 * @throws \ArchivedObjectException
+	 * @throws \CoreException
 	 * @throws \OQLException
 	 */
 	static public function unserialize($sValue)
 	{
-		$aData = unserialize(base64_decode(rawurldecode($sValue)));
+		$aData = json_decode(rawurldecode($sValue), true);
 		$sOql = $aData[0];
 		$aParams = $aData[1];
+		$aExtraParams = array();
+		foreach($aParams as $sParam => $sValue)
+		{
+			if (($iPos = strpos($sParam, '->class')) !== false)
+			{
+				$sParamName = substr($sParam, 0, $iPos);
+				if (isset($aParams[$sParamName.'->id']))
+				{
+					$sClass = $aParams[$sParamName.'->class'];
+					$iKey = $aParams[$sParamName.'->id'];
+					$oObj = MetaModel::GetObject($sClass, $iKey);
+					$aExtraParams[$sParamName.'->object()'] = $oObj;
+				}
+			}
+		}
+		$aParams = array_merge($aExtraParams, $aParams);
 		// We've tried to use gzcompress/gzuncompress, but for some specific queries
 		// it was not working at all (See Trac #193)
 		// gzuncompress was issuing a warning "data error" and the return object was null
diff --git a/test/testlist.inc.php b/test/testlist.inc.php
index 88519843a..434bd5104 100644
--- a/test/testlist.inc.php
+++ b/test/testlist.inc.php
@@ -728,7 +728,7 @@ class TestQueriesOnFarm extends MyFarm
 		$oFilter2 = DBObjectSearch::unserialize($sSerialize);
 		try
 		{
-			$sQuery2 = $oMyFilter2->MakeSelectQuery();
+			$sQuery2 = $oFilter2->MakeSelectQuery();
 		}
 		catch (Exception $e)
 		{