diff --git a/src/data/extra/web/js/graphpreviewer.js b/src/data/extra/web/js/graphpreviewer.js
index 97ff5556..d010a6cb 100644
--- a/src/data/extra/web/js/graphpreviewer.js
+++ b/src/data/extra/web/js/graphpreviewer.js
@@ -26,19 +26,14 @@ class GraphPreviewer {
             { passive: true });
     }
 
+    // Interface 1.
     previewGraph(p_id, p_timeStamp, p_lang, p_text) {
         if (p_text.length == 0) {
             this.setGraphPreviewData(p_id, p_timeStamp);
             return;
         }
 
-        if (this.firstPreview) {
-            this.firstPreview = false;
-
-            let contentStyle = window.getComputedStyle(this.vnotex.contentContainer);
-            this.currentColor = contentStyle.getPropertyValue('color');
-            console.log('currentColor', this.currentColor);
-        }
+        this.initOnFirstPreview();
 
         if (p_lang === 'flow' || p_lang === 'flowchart') {
             this.vnotex.getWorker('flowchartjs').renderText(this.container,
@@ -92,6 +87,29 @@ class GraphPreviewer {
         }
     }
 
+    // Interface 2.
+    previewMath(p_id, p_timeStamp, p_text) {
+        if (p_text.length == 0) {
+            this.setMathPreviewData(p_id, p_timeStamp);
+            return;
+        }
+
+        this.initOnFirstPreview();
+
+        // Do we need to go through TexMath plugin? I don't think so.
+        this.renderMath(p_id, p_timeStamp, p_text, this.setMathPreviewData.bind(this));
+    }
+
+    initOnFirstPreview() {
+        if (this.firstPreview) {
+            this.firstPreview = false;
+
+            let contentStyle = window.getComputedStyle(this.vnotex.contentContainer);
+            this.currentColor = contentStyle.getPropertyValue('color');
+            console.log('currentColor', this.currentColor);
+        }
+    }
+
     renderMath(p_id, p_timeStamp, p_text, p_dataSetter) {
         let func = function(p_previewer, p_id, p_timeStamp) {
             let previewer = p_previewer;
@@ -162,11 +180,6 @@ class GraphPreviewer {
         });
     }
 
-    previewMath(p_id, p_timeStamp, p_text) {
-        // Do we need to go through TexMath plugin? I don't think so.
-        this.renderMath(p_id, p_timeStamp, p_text, this.setMathPreviewData.bind(this));
-    }
-
     // Fix SVG with width and height being '100%'.
     fixSvgRelativeWidth(p_svgNode) {
         if (p_svgNode.getAttribute('width').indexOf('%') != -1) {
diff --git a/src/widgets/viewwindow.cpp b/src/widgets/viewwindow.cpp
index 3cdfe755..14b7b9a7 100644
--- a/src/widgets/viewwindow.cpp
+++ b/src/widgets/viewwindow.cpp
@@ -753,8 +753,9 @@ int ViewWindow::checkFileMissingOrChangedOutside()
     } else if (m_buffer->checkFileChangedOutside()) {
         int ret = MessageBoxHelper::questionSaveDiscardCancel(MessageBoxHelper::Warning,
             tr("File is changed from outside (%1).").arg(m_buffer->getPath()),
-            tr("Do you want to override the file from buffer?"),
-            tr("The file is changed from outside. Please choose to save the buffer to the file or just discard the buffer and reload the file."),
+            tr("Do you want to save the buffer to the file to override, or discard the buffer?"),
+            tr("The file is changed from outside. Please choose to save the buffer to the file or "
+               "just discard the buffer and reload the file."),
             this);
         switch (ret) {
         case QMessageBox::Save: