diff --git a/api/src/org/labkey/api/view/menu/NavTreeMenu.java b/api/src/org/labkey/api/view/menu/NavTreeMenu.java
index a5e57e8a607..7345d4092a8 100644
--- a/api/src/org/labkey/api/view/menu/NavTreeMenu.java
+++ b/api/src/org/labkey/api/view/menu/NavTreeMenu.java
@@ -201,10 +201,11 @@ private void renderLinks(NavTree nav, int level, String pathToHere, String rootI
                 ActionURL expandCollapseUrl = Objects.requireNonNull(PageFlowUtil.urlProvider(ProjectUrls.class)).getExpandCollapseURL(getViewContext().getContainer(), pathToHere, rootId);
 
                 String image = collapsed ? "plus.gif" : "minus.gif";
+                String altPrefix = collapsed ? "Expand" : "Collapse";
                 id = config.makeId("navtree");
                 oldWriter.printf("<a id=\"%s\" href=\"%s\">", id, filter(expandCollapseUrl));
                 config.addHandler(id, "click", "return LABKEY.Utils.toggleLink(this,true);");
-                oldWriter.printf("<img src=\"%s/_images/%s\" width=9 height=9></a>", context.getContextPath(), image);
+                oldWriter.printf("<img src=\"%s/_images/%s\" width=9 height=9 alt=\"%s %s\"></a>", filter(context.getContextPath()), filter(image), filter(altPrefix), filter(nav.getText()));
             }
             else if (indentForExpansionGifs)
                 oldWriter.printf("<div class=\"labkey-nav-tree-indenter\"></div>");
diff --git a/core/src/org/labkey/core/view/template/bootstrap/ViewServiceImpl.java b/core/src/org/labkey/core/view/template/bootstrap/ViewServiceImpl.java
index 08c7d618fe2..23885cce85e 100644
--- a/core/src/org/labkey/core/view/template/bootstrap/ViewServiceImpl.java
+++ b/core/src/org/labkey/core/view/template/bootstrap/ViewServiceImpl.java
@@ -666,7 +666,7 @@ public void renderCollapsiblePortalTitle(PrintWriter out)
 
         public void renderCustomDropDown(String title, NavTree current, PrintWriter out)
         {
-            renderMenuWithFontImage(null, current, out, null, false);
+            renderMenuWithFontImage(title, current, out, null, false);
         }
     }
 
@@ -750,7 +750,9 @@ private void renderMenuWithFontImage(String title, NavTree menu, PrintWriter out
             if (rightAlign)
                 out.print(" pull-right");
             out.print("\">");
-            out.print("<a href=\"#\" data-toggle=\"dropdown\" class=\"dropdown-toggle ");
+            out.print("<a href=\"#\" aria-label=\"");
+            out.print(filter(title) + " webpart options");
+            out.print("\" data-toggle=\"dropdown\" class=\"dropdown-toggle ");
             out.print(!StringUtils.isEmpty(imageCls) ? imageCls : !StringUtils.isEmpty(menu.getImageCls()) ? menu.getImageCls() : "");
             out.print("\">");
             out.print("</a>");
diff --git a/core/src/org/labkey/core/view/template/bootstrap/header.jsp b/core/src/org/labkey/core/view/template/bootstrap/header.jsp
index e147df531db..a5d95b301f5 100644
--- a/core/src/org/labkey/core/view/template/bootstrap/header.jsp
+++ b/core/src/org/labkey/core/view/template/bootstrap/header.jsp
@@ -143,7 +143,7 @@
     {
 %>
             <li class="navbar-search hidden-xs">
-                <a class="fa fa-search" id="global-search-trigger"></a>
+                <a class="fa fa-search" id="global-search-trigger" aria-label="<%=h(SearchUtils.getPlaceholder(c))%>"></a>
                 <div id="global-search" class="global-search">
                     <labkey:form id="global-search-form" action="<%=urlProvider(SearchUrls.class).getSearchURL(c, null)%>" method="GET">
                         <input type="text" class="search-box" name="q" placeholder="<%=h(SearchUtils.getPlaceholder(c))%>" value="">
diff --git a/experiment/src/org/labkey/experiment/api/ExpUnreferencedSampleFilesTableImpl.java b/experiment/src/org/labkey/experiment/api/ExpUnreferencedSampleFilesTableImpl.java
index fb4cbe5ab2f..ffd0e429609 100644
--- a/experiment/src/org/labkey/experiment/api/ExpUnreferencedSampleFilesTableImpl.java
+++ b/experiment/src/org/labkey/experiment/api/ExpUnreferencedSampleFilesTableImpl.java
@@ -48,38 +48,42 @@ public FileUnionTable(@NotNull ExpSchema schema)
             FileContentService svc = FileContentService.get();
 
             _query = new SQLFragment();
-            if (svc == null)
-                return;
-
-            SQLFragment listQuery = svc.listSampleFilesQuery(schema.getUser());
-            if (StringUtils.isEmpty(listQuery))
-                return;
-
-            TableInfo expDataTable = ExperimentService.get().getTinfoData();
-            TableInfo materialTable = ExperimentService.get().getTinfoMaterial();
+            SQLFragment listQuery = new SQLFragment();
+            if (svc != null)
+                listQuery = svc.listSampleFilesQuery(schema.getUser());
 
             _query.appendComment("<SampleFileListTableInfo>", getSchema().getSqlDialect());
 
-            SQLFragment sampleFileSql = new SQLFragment("SELECT m.Container, if.FilePathShort \n")
-                    .append("FROM (")
-                    .append(svc.listSampleFilesQuery(schema.getUser()))
-                    .append(") AS if \n")
-                    .append("JOIN ")
-                    .append(materialTable, "m")
-                    .append(" ON if.SourceKey = m.RowId");
-
-            SQLFragment unreferencedFileSql = new SQLFragment("SELECT ed.rowId, ed.name as filename, ed.container, ed.created, ed.createdBy, ed.DataFileUrl FROM ")
-                    .append(expDataTable, "ed")
-                    .append(" LEFT JOIN (")
-                    .append(sampleFileSql)
-                    .append(" ) sf\n")
-                    .append(" ON ed.name = sf.FilePathShort AND ed.container = sf.container\n")
-                    .append(" WHERE ed.datafileurl LIKE ")
-                    .appendValue("%@files/sampletype/%")
-                    .append(" AND sf.FilePathShort IS NULL");
-
-            _query.append(unreferencedFileSql);
+            TableInfo expDataTable = ExperimentService.get().getTinfoData();
+            if (!StringUtils.isEmpty(listQuery))
+            {
+                TableInfo materialTable = ExperimentService.get().getTinfoMaterial();
+
+                SQLFragment sampleFileSql = new SQLFragment("SELECT m.Container, if.FilePathShort \n")
+                        .append("FROM (")
+                        .append(listQuery)
+                        .append(") AS if \n")
+                        .append("JOIN ")
+                        .append(materialTable, "m")
+                        .append(" ON if.SourceKey = m.RowId");
+
+                SQLFragment unreferencedFileSql = new SQLFragment("SELECT ed.rowId, ed.name as filename, ed.container, ed.created, ed.createdBy, ed.DataFileUrl FROM ")
+                        .append(expDataTable, "ed")
+                        .append(" LEFT JOIN (")
+                        .append(sampleFileSql)
+                        .append(" ) sf\n")
+                        .append(" ON ed.name = sf.FilePathShort AND ed.container = sf.container\n")
+                        .append(" WHERE ed.datafileurl LIKE ")
+                        .appendValue("%@files/sampletype/%")
+                        .append(" AND sf.FilePathShort IS NULL");
+
+                _query.append(unreferencedFileSql);
 
+            }
+            else
+            {
+                _query.append("SELECT RowId, Name AS FileName, Container, Created, CreatedBy, DataFileUrl FROM ").append(expDataTable).append(" WHERE (1=0)");
+            }
             _query.appendComment("</SampleFileListTableInfo>", getSchema().getSqlDialect());
 
             var rowIdCol = new BaseColumnInfo("RowId", this, JdbcType.INTEGER);
diff --git a/query/src/org/labkey/query/controllers/QueryController.java b/query/src/org/labkey/query/controllers/QueryController.java
index 35ba9a5d411..0ed4aa66be9 100644
--- a/query/src/org/labkey/query/controllers/QueryController.java
+++ b/query/src/org/labkey/query/controllers/QueryController.java
@@ -714,7 +714,8 @@ public DataSourceAdminAction(ViewContext viewContext)
         public ModelAndView getView(Object o, BindException errors)
         {
             // Site Admin or Troubleshooter? Troubleshooters can see all the information but can't test data sources.
-            boolean hasAdminOpsPerms = getContainer().hasPermission(getUser(), AdminOperationsPermission.class);
+            // Dev mode only, since "Test" is meant for LabKey's own development and testing purposes.
+            boolean showTestButton = getContainer().hasPermission(getUser(), AdminOperationsPermission.class) && AppProps.getInstance().isDevMode();
             List<ExternalSchemaDef> allDefs = QueryManager.get().getExternalSchemaDefs(null);
 
             MultiValuedMap<String, ExternalSchemaDef> byDataSourceName = new ArrayListValuedHashMap<>();
@@ -729,7 +730,7 @@ public ModelAndView getView(Object o, BindException errors)
                 BR(),
                 TABLE(cl("labkey-data-region"),
                     TR(cl("labkey-show-borders"),
-                        hasAdminOpsPerms ? TD(cl("labkey-column-header"), "Test") : null,
+                        showTestButton ? TD(cl("labkey-column-header"), "Test") : null,
                         TD(cl("labkey-column-header"), "Data Source"),
                         TD(cl("labkey-column-header"), "Current Status"),
                         TD(cl("labkey-column-header"), "URL"),
@@ -759,7 +760,7 @@ public ModelAndView getView(Object o, BindException errors)
                             return Stream.of(
                                 TR(
                                     cl(rowStyle),
-                                    hasAdminOpsPerms ? TD(connected ? new ButtonBuilder("Test").href(new ActionURL(TestDataSourceConfirmAction.class, getContainer()).addParameter("dataSource", scope.getDataSourceName())) : "") : null,
+                                    showTestButton ? TD(connected ? new ButtonBuilder("Test").href(new ActionURL(TestDataSourceConfirmAction.class, getContainer()).addParameter("dataSource", scope.getDataSourceName())) : "") : null,
                                     TD(HtmlString.NBSP, scope.getDisplayName()),
                                     TD(status),
                                     TD(scope.getDatabaseUrl()),
diff --git a/search/src/org/labkey/search/view/search.jsp b/search/src/org/labkey/search/view/search.jsp
index 3fd522f86e3..56a9e851d26 100644
--- a/search/src/org/labkey/search/view/search.jsp
+++ b/search/src/org/labkey/search/view/search.jsp
@@ -294,7 +294,7 @@
     <div style="position:relative;">
         <labkey:form id="<%=searchFormId%>" className="lk-search-form" action="<%=searchConfig.getPostURL(c)%>">
             <labkey:input type="text" name="q" placeholder="<%=form.isWebPart() ? \"\" : SearchUtils.getPlaceholder(c)%>" formGroup="false" value="<%=value%>"/>
-            <a class="search-overlay fa fa-search"></a>
+            <a class="search-overlay fa fa-search" aria-label="<%= h(SearchUtils.getPlaceholder(c)) %>"></a>
             <% if (showAdvancedUI) { %>
             <small>
                 <a class="search-advanced-toggle">advanced options</a>
diff --git a/wiki/src/org/labkey/wiki/WikiController.java b/wiki/src/org/labkey/wiki/WikiController.java
index a26266905d8..a9c9c35cc7a 100644
--- a/wiki/src/org/labkey/wiki/WikiController.java
+++ b/wiki/src/org/labkey/wiki/WikiController.java
@@ -427,7 +427,7 @@ public ActionURL getCancelUrl()
         @Override
         public ActionURL getFailURL(WikiNameForm wikiNameForm, BindException errors)
         {
-            return new ManageAction(getViewContext(), _wiki).getUrl();
+            return _wiki != null ? new ManageAction(getViewContext(), _wiki).getUrl() : null;
         }
     }