allow closing tabs; ask confirmation if content is changed

src/dlangide/ui/frame.d

@@ -123,6 +123,39 @@ class IDEFrame : AppFrame {
         }
     }
 
+    /// close tab w/o confirmation
+    void closeTab(string tabId) {
+        _wsPanel.selectItem(null);
+        _tabs.removeTab(tabId);
+    }
+
+    protected void onTabClose(string tabId) {
+        Log.d("onTabClose ", tabId);
+        int index = _tabs.tabIndex(tabId);
+        if (index >= 0) {
+            DSourceEdit d = cast(DSourceEdit)_tabs.tabBody(tabId);
+            if (d && d.content.modified) {
+                // tab content is modified - ask for confirmation
+                window.showMessageBox(UIString("Close tab"d), UIString("Content of "d ~ toUTF32(baseName(id)) ~ " file has been changed."d), 
+                                      [ACTION_SAVE, ACTION_DISCARD_CHANGES, ACTION_CANCEL], 
+                                      0, delegate(const Action result) {
+                                          if (result == StandardAction.Save) {
+                                              // save and close
+                                              d.save();
+                                              closeTab(tabId);
+                                          } else if (result == StandardAction.DiscardChanges) {
+                                              // close, don't save
+                                              closeTab(tabId);
+                                          }
+                                          // else ignore
+                                          return true;
+                                      });
+            } else {
+                closeTab(tabId);
+            }
+        }
+    }
+
     /// create app body widget
     override protected Widget createBody() {
         _dockHost = new DockHost();
@@ -134,7 +167,8 @@ class IDEFrame : AppFrame {
         _tabs = new TabWidget("TABS");
         _tabs.setStyles(STYLE_DOCK_HOST_BODY, STYLE_TAB_UP_DARK, STYLE_TAB_UP_BUTTON_DARK, STYLE_TAB_UP_BUTTON_DARK_TEXT);
         _tabs.onTabChangedListener = &onTabChanged;
-        
+        _tabs.onTabCloseListener = &onTabClose;
+
         _dockHost.bodyWidget = _tabs;
 
         //=============================================================

src/dlangide/ui/wspanel.d

@@ -31,15 +31,22 @@ class WorkspacePanel : DockWindow {
     }
 
     bool selectItem(ProjectItem projectItem) {
-        TreeItem item = _tree.findItemById(projectItem.filename);
-        if (item) {
-            _tree.selectItem(item);
+        if (projectItem) {
+            TreeItem item = _tree.findItemById(projectItem.filename);
+            if (item) {
+                _tree.selectItem(item);
+                return true;
+            }
+        } else {
+            _tree.clearSelection();
             return true;
         }
         return false;
     }
 
     void onTreeItemSelected(TreeItems source, TreeItem selectedItem, bool activated) {
+        if (!selectedItem)
+            return;
         if (selectedItem.intParam == ProjectItemType.SourceFile) {
             // file selected
             if (sourceFileSelectionListener.assigned) {

workspaces/sample1/sampleproject1/source/main.d

@@ -1,7 +1,6 @@
 void main() {
 
 
-///
 
 }