NetworkPanel: Make "sticky" behavior explicit.

Source/devtools/front_end/inspector.css

Index: Source/devtools/front_end/inspector.css
diff --git a/Source/devtools/front_end/inspector.css b/Source/devtools/front_end/inspector.css
index 6886b557198ad72667e8c7f2d76370f198b94cc6..4f85bfea6d52f90baf8386420c1d169e7297d0c6 100644
--- a/Source/devtools/front_end/inspector.css
+++ b/Source/devtools/front_end/inspector.css
@@ -554,6 +554,10 @@ select.status-bar-item {
     line-height: 20px;
 }
 
+.status-bar-item.checkbox {
+    margin: 2px 0 0 0;
+}
+
 .status-bar-item > .glyph {
     -webkit-mask-image: url(Images/statusbarButtonGlyphs.png);
     -webkit-mask-size: 320px 120px;