diff --git a/core/fpdfdoc/cpdf_annot.cpp b/core/fpdfdoc/cpdf_annot.cpp
index 4559fc4..14533f5 100644
--- a/core/fpdfdoc/cpdf_annot.cpp
+++ b/core/fpdfdoc/cpdf_annot.cpp
@@ -482,7 +482,7 @@
   } else {
     ByteString style = pBS->GetStringFor("S");
     pDashArray = pBS->GetArrayFor("D");
-    style_char = style[1];
+    style_char = style[0];
     width = pBS->GetNumberFor("W");
   }
   if (width <= 0) {
@@ -498,6 +498,12 @@
   }
   CFX_GraphStateData graph_state;
   graph_state.m_LineWidth = width;
+  if (style_char == 'U') {
+    // TODO(https://crbug.com/237527): Handle the "Underline" border style
+    // instead of drawing the rectangle border.
+    return;
+  }
+
   if (style_char == 'D') {
     if (pDashArray) {
       graph_state.m_DashArray =
diff --git a/core/fpdfdoc/cpdf_annotlist.cpp b/core/fpdfdoc/cpdf_annotlist.cpp
index 64ecffb..6b53b64 100644
--- a/core/fpdfdoc/cpdf_annotlist.cpp
+++ b/core/fpdfdoc/cpdf_annotlist.cpp
@@ -289,6 +289,7 @@
 }
 
 void CPDF_AnnotList::DisplayAnnots(CPDF_Page* pPage,
+                                   CFX_RenderDevice* device,
                                    CPDF_RenderContext* pContext,
                                    bool bPrinting,
                                    const CFX_Matrix* pMatrix,
@@ -297,6 +298,6 @@
   uint32_t dwAnnotFlags = bShowWidget ? pdfium::annotation_flags::kInvisible |
                                             pdfium::annotation_flags::kHidden
                                       : pdfium::annotation_flags::kInvisible;
-  DisplayAnnots(pPage, nullptr, pContext, bPrinting, pMatrix, dwAnnotFlags,
+  DisplayAnnots(pPage, device, pContext, bPrinting, pMatrix, dwAnnotFlags,
                 pOptions, nullptr);
 }
diff --git a/core/fpdfdoc/cpdf_annotlist.h b/core/fpdfdoc/cpdf_annotlist.h
index 85075cf..583ffce 100644
--- a/core/fpdfdoc/cpdf_annotlist.h
+++ b/core/fpdfdoc/cpdf_annotlist.h
@@ -28,6 +28,7 @@
   ~CPDF_AnnotList() override;
 
   void DisplayAnnots(CPDF_Page* pPage,
+                     CFX_RenderDevice* device,
                      CPDF_RenderContext* pContext,
                      bool bPrinting,
                      const CFX_Matrix* pMatrix,
diff --git a/fpdfsdk/cpdfsdk_renderpage.cpp b/fpdfsdk/cpdfsdk_renderpage.cpp
index ab3ce61..42fd11e 100644
--- a/fpdfsdk/cpdfsdk_renderpage.cpp
+++ b/fpdfsdk/cpdfsdk_renderpage.cpp
@@ -70,8 +70,9 @@
     pContext->m_pAnnots = std::move(pOwnedList);
     bool bPrinting =
         pContext->m_pDevice->GetDeviceType() != DeviceType::kDisplay;
-    pList->DisplayAnnots(pPage, pContext->m_pContext.get(), bPrinting, &matrix,
-                         false, nullptr);
+    pList->DisplayAnnots(pPage, pContext->m_pDevice.get(),
+                         pContext->m_pContext.get(), bPrinting, &matrix, false,
+                         nullptr);
   }
 
   pContext->m_pRenderer = std::make_unique<CPDF_ProgressiveRenderer>(