Don't update selection when folder window in background; fix #79

src/FolderWindow.cpp

@@ -158,6 +158,10 @@ void FolderWindow::onActivate(WORD state, HWND prevWindow) {
             activateOnShiftRelease = GetKeyState(VK_SHIFT) < 0;
             checkHR(shellView->UIActivate(SVUIA_ACTIVATE_FOCUS));
         }
+        if (updateSelectionOnActivate) {
+            selectionChanged();
+            updateSelectionOnActivate = false;
+        }
     }
 }
 
@@ -301,9 +305,13 @@ STDMETHODIMP FolderWindow::OnDefaultCommand(IShellView *) {
 STDMETHODIMP FolderWindow::OnStateChange(IShellView *, ULONG change) {
     if (change == CDBOSC_SELCHANGE) {
         if (!ignoreNextSelection) {
-            // TODO this can hang the browser and should really be done asynchronously with a message
-            // but that adds other complication
-            selectionChanged();
+            if (GetActiveWindow() != hwnd) {
+                // this could happen when dragging a file. don't try to create any windows yet
+                updateSelectionOnActivate = true;
+            } else {
+                selectionChanged();
+                updateSelectionOnActivate = false;
+            }
         }
         ignoreNextSelection = false;
     }

src/FolderWindow.h

@@ -54,6 +54,7 @@ class FolderWindow : public ItemWindow, public IServiceProvider, public ICommDlg
 
     // jank flags
     bool ignoreNextSelection = false;
+    bool updateSelectionOnActivate = false;
     bool activateOnShiftRelease = false;
 };
 

src/ItemWindow.cpp

@@ -170,7 +170,7 @@ bool ItemWindow::create(RECT rect, int showCommand) {
     else if (child)
         owner = GetWindowOwner(child->hwnd);
     else
-        owner = createChainOwner();
+        owner = createChainOwner(showCommand);
 
     HWND createHwnd = CreateWindow(
         className(), title,
@@ -191,10 +191,10 @@ bool ItemWindow::create(RECT rect, int showCommand) {
     return true;
 }
 
-HWND ItemWindow::createChainOwner() {
+HWND ItemWindow::createChainOwner(int showCommand) {
     HWND window = CreateWindow(CHAIN_OWNER_CLASS, nullptr, WS_POPUP, 0, 0, 0, 0,
         nullptr, nullptr, GetModuleHandle(nullptr), 0); // user data stores num owned windows
-    ShowWindow(window, SW_SHOWNORMAL); // show in taskbar
+    ShowWindow(window, showCommand); // show in taskbar
     return window;
 }
 
@@ -724,7 +724,7 @@ void ItemWindow::detachFromParent() {
     clearParent();
     ShowWindow(parentButton, SW_SHOW);
     HWND prevOwner = GetWindowOwner(hwnd);
-    HWND owner = createChainOwner();
+    HWND owner = createChainOwner(SW_SHOWNORMAL);
     int numChildren = 0;
     for (ItemWindow *next = this; next != nullptr; next = next->child) {
         SetWindowLongPtr(next->hwnd, GWLP_HWNDPARENT, (LONG_PTR)owner);

src/ItemWindow.h

@@ -80,7 +80,7 @@ class ItemWindow : public IUnknownImpl, public IDropSource, public IDropTarget {
 private:
     virtual const wchar_t * className() = 0;
 
-    HWND createChainOwner();
+    HWND createChainOwner(int showCommand);
 
     void windowRectChanged();
     void bringGroupToFront();