DevTools: do not detach views that should be hidden upon detach.

Source/devtools/front_end/splitView.css

Index: Source/devtools/front_end/splitView.css
diff --git a/Source/devtools/front_end/splitView.css b/Source/devtools/front_end/splitView.css
index 9680cf9cbbeea6c85b66f95f173ac37ed04a41ce..058a0c838766bca460ec7a5f3c1da8aa276cb5b8 100644
--- a/Source/devtools/front_end/splitView.css
+++ b/Source/devtools/front_end/splitView.css
@@ -62,6 +62,14 @@
     z-index: 500;
 }
 
+.split-view.hbox.split-view-first-is-sidebar {
+    flex-direction: row-reverse !important;
+}
+
+.split-view.vbox.split-view-first-is-sidebar {
+    flex-direction: column-reverse !important;
+}
+
 .split-view-resizer-border {
     pointer-events: none;
 }