Switch from preview to edit by double click

User want to click markdown to work with text (for example copy).
If they have "Switch to Preview" setting in "When Editor Blurred",
they enter edit mode after click. To fix that issue I introduced new
value to the "Switch to Preview" setting that do that thing. User can
enter edit mode by double click on the editor and leave it on blur.

Unfortunately, it's impossible to switch both ways by double click
because the editor mode is listening for double click event.

#1523

browser/components/MarkdownEditor.js

@@ -92,7 +92,9 @@ class MarkdownEditor extends React.Component {
     if (this.state.isLocked) return
     this.setState({ keyPressed: new Set() })
     const { config } = this.props
-    if (config.editor.switchPreview === 'BLUR') {
+    if (config.editor.switchPreview === 'BLUR' ||
+        (config.editor.switchPreview === 'DBL_CLICK' && this.state.status === 'CODE')
+    ) {
       const cursorPosition = this.refs.code.editor.getCursor()
       this.setState({
         status: 'PREVIEW'
@@ -104,6 +106,20 @@ class MarkdownEditor extends React.Component {
     }
   }
 
+  handleDoubleClick (e) {
+    if (this.state.isLocked) return
+    this.setState({keyPressed: new Set()})
+    const { config } = this.props
+    if (config.editor.switchPreview === 'DBL_CLICK') {
+      this.setState({
+        status: 'CODE'
+      }, () => {
+        this.refs.code.focus()
+        eventEmitter.emit('topbar:togglelockbutton', this.state.status)
+      })
+    }
+  }
+
   handlePreviewMouseDown (e) {
     this.previewMouseDownedAt = new Date()
   }
@@ -264,6 +280,7 @@ class MarkdownEditor extends React.Component {
           scrollPastEnd={config.preview.scrollPastEnd}
           ref='preview'
           onContextMenu={(e) => this.handleContextMenu(e)}
+          onDoubleClick={(e) => this.handleDoubleClick(e)}
           tabIndex='0'
           value={this.state.renderValue}
           onMouseUp={(e) => this.handlePreviewMouseUp(e)}

browser/components/MarkdownPreview.js

@@ -120,6 +120,7 @@ export default class MarkdownPreview extends React.Component {
     this.contextMenuHandler = (e) => this.handleContextMenu(e)
     this.mouseDownHandler = (e) => this.handleMouseDown(e)
     this.mouseUpHandler = (e) => this.handleMouseUp(e)
+    this.DoubleClickHandler = (e) => this.handleDoubleClick(e)
     this.anchorClickHandler = (e) => this.handlePreviewAnchorClick(e)
     this.checkboxClickHandler = (e) => this.handleCheckboxClick(e)
     this.saveAsTextHandler = () => this.handleSaveAsText()
@@ -154,6 +155,10 @@ export default class MarkdownPreview extends React.Component {
     this.props.onContextMenu(e)
   }
 
+  handleDoubleClick (e) {
+    if (this.props.onDoubleClick != null) this.props.onDoubleClick(e)
+  }
+
   handleMouseDown (e) {
     if (e.target != null) {
       switch (e.target.tagName) {
@@ -271,6 +276,7 @@ export default class MarkdownPreview extends React.Component {
 
     this.refs.root.contentWindow.document.addEventListener('mousedown', this.mouseDownHandler)
     this.refs.root.contentWindow.document.addEventListener('mouseup', this.mouseUpHandler)
+    this.refs.root.contentWindow.document.addEventListener('dblclick', this.DoubleClickHandler)
     this.refs.root.contentWindow.document.addEventListener('drop', this.preventImageDroppedHandler)
     this.refs.root.contentWindow.document.addEventListener('dragover', this.preventImageDroppedHandler)
     eventEmitter.on('export:save-text', this.saveAsTextHandler)
@@ -283,6 +289,7 @@ export default class MarkdownPreview extends React.Component {
     this.refs.root.contentWindow.document.body.removeEventListener('contextmenu', this.contextMenuHandler)
     this.refs.root.contentWindow.document.removeEventListener('mousedown', this.mouseDownHandler)
     this.refs.root.contentWindow.document.removeEventListener('mouseup', this.mouseUpHandler)
+    this.refs.root.contentWindow.document.removeEventListener('dblclick', this.DoubleClickHandler)
     this.refs.root.contentWindow.document.removeEventListener('drop', this.preventImageDroppedHandler)
     this.refs.root.contentWindow.document.removeEventListener('dragover', this.preventImageDroppedHandler)
     eventEmitter.off('export:save-text', this.saveAsTextHandler)

browser/main/modals/PreferencesModal/UiTab.js

@@ -283,6 +283,7 @@ class UiTab extends React.Component {
                 onChange={(e) => this.handleUIChange(e)}
               >
                 <option value='BLUR'>When Editor Blurred</option>
+                <option value='DBL_CLICK'>When Editor Blurred, Edit On Double Click</option>
                 <option value='RIGHTCLICK'>On Right Click</option>
               </select>
             </div>