Bug 548056 - Add space in "Show whitespace" preference label

There is no space in the GUI label between the
"Show whitespace characters" text and the  "(configure visibility)"
text on GTK.

Change-Id: I74f4b747c8fc6f6de09e6549cb417bb03336f39a
Signed-off-by: Jens Lidestrom <jens@lidestrom.se>
diff --git a/org.eclipse.ui.editors/src/org/eclipse/ui/internal/editors/text/TextEditorDefaultsPreferencePage.java b/org.eclipse.ui.editors/src/org/eclipse/ui/internal/editors/text/TextEditorDefaultsPreferencePage.java
index a5aae89..ca99182 100644
--- a/org.eclipse.ui.editors/src/org/eclipse/ui/internal/editors/text/TextEditorDefaultsPreferencePage.java
+++ b/org.eclipse.ui.editors/src/org/eclipse/ui/internal/editors/text/TextEditorDefaultsPreferencePage.java
@@ -48,6 +48,7 @@
 
 import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.Platform;
 
 import org.eclipse.jface.dialogs.Dialog;
 import org.eclipse.jface.dialogs.DialogPage;
@@ -1290,7 +1291,8 @@
 		GridLayout layout= new GridLayout();
 		layout.marginHeight= 0;
 		layout.marginWidth= 0;
-		layout.horizontalSpacing= 0;
+		// The spacing between the controls is different on GTK
+		layout.horizontalSpacing= Platform.WS_GTK.equals(Platform.getWS()) ? 4 : 0;
 		layout.numColumns= 2;
 		composite.setLayout(layout);
 		composite.setLayoutData(gd);