IDEA-169940 Get rid of gradient popup titles

* title size and insets are changed

platform/util/src/com/intellij/ui/TitlePanel.java

@@ -48,7 +48,7 @@ public class TitlePanel extends CaptionPanel {
     myLabel.setForeground(JBColor.foreground());
     myLabel.setHorizontalAlignment(SwingConstants.CENTER);
     myLabel.setVerticalAlignment(SwingConstants.CENTER);
-    myLabel.setBorder(JBUI.Borders.empty(1, 2, 2, 2));
+    myLabel.setBorder(JBUI.Borders.empty(1, 10, 2, 10));
 
     add(myLabel, BorderLayout.CENTER);
 
@@ -80,6 +80,7 @@ public class TitlePanel extends CaptionPanel {
     }
 
     final Dimension preferredSize = super.getPreferredSize();
+    preferredSize.height = JBUI.CurrentTheme.Popup.headerHeight();
     int maxWidth = JBUI.scale(350);
     if (!myHtml && preferredSize.width > maxWidth) { // do not allow caption to extend parent container
       return new Dimension(maxWidth, preferredSize.height);

platform/util/src/com/intellij/util/ui/JBUI.java

@@ -1536,6 +1536,10 @@ public class JBUI {
                : getColor("Popup.Header.inactiveBackground", 0xededed);
       }
 
+      public static int headerHeight() {
+        return scale(24);
+      }
+
       public static Color borderColor(boolean active) {
         return active
                ? getColor("Popup.Border.color", 0x808080)