commit 4bfc5a7c6d8c2aaf954c113d805419472de2bcaf
Author: Mat Booth <mat.booth@redhat.com>
Date:   Thu May 3 15:58:49 2018 +0100

    Bug 534326 - Awkward p2 UI when many droplets are installed
    
    Filter out software site locations where we know that they are p2
    droplets in places we show the list to the user.
    
    Change-Id: I12364223850862783cb7cffd32fb7428fbf6b270
    Signed-off-by: Mat Booth <mat.booth@redhat.com>

diff --git a/rt.equinox.p2/bundles/org.eclipse.equinox.p2.ui/src/org/eclipse/equinox/internal/p2/ui/dialogs/RepositorySelectionGroup.java b/rt.equinox.p2/bundles/org.eclipse.equinox.p2.ui/src/org/eclipse/equinox/internal/p2/ui/dialogs/RepositorySelectionGroup.java
index e6eef8c39..fe5970e79 100644
--- a/rt.equinox.p2/bundles/org.eclipse.equinox.p2.ui/src/org/eclipse/equinox/internal/p2/ui/dialogs/RepositorySelectionGroup.java
+++ b/rt.equinox.p2/bundles/org.eclipse.equinox.p2.ui/src/org/eclipse/equinox/internal/p2/ui/dialogs/RepositorySelectionGroup.java
@@ -300,6 +300,19 @@ public class RepositorySelectionGroup {
 	void fillRepoCombo(final String selection) {
 		RepositoryTracker tracker = ui.getRepositoryTracker();
 		URI[] sites = tracker.getKnownRepositories(ui.getSession());
+		// Filter out sites that are actually installed p2 droplets
+		String fragments = System.getProperty("p2.fragments"); //$NON-NLS-1$
+		ArrayList<URI> filteredSites = new ArrayList<>(Arrays.asList(sites));
+		if (fragments != null) {
+			for (String root : fragments.split(",")) { //$NON-NLS-1$
+				for (URI uri : sites) {
+					if (uri.getPath() != null && uri.getPath().startsWith(root)) {
+						filteredSites.remove(uri);
+					}
+				}
+			}
+		}
+		sites = filteredSites.toArray(new URI[0]);
 		boolean hasLocalSites = getLocalSites().length > 0;
 		final String[] items;
 		if (hasLocalSites) {
diff --git a/rt.equinox.p2/bundles/org.eclipse.equinox.p2.ui/src/org/eclipse/equinox/p2/ui/RepositoryManipulationPage.java b/rt.equinox.p2/bundles/org.eclipse.equinox.p2.ui/src/org/eclipse/equinox/p2/ui/RepositoryManipulationPage.java
index d796aefd0..c03924f90 100644
--- a/rt.equinox.p2/bundles/org.eclipse.equinox.p2.ui/src/org/eclipse/equinox/p2/ui/RepositoryManipulationPage.java
+++ b/rt.equinox.p2/bundles/org.eclipse.equinox.p2.ui/src/org/eclipse/equinox/p2/ui/RepositoryManipulationPage.java
@@ -130,9 +130,22 @@ public class RepositoryManipulationPage extends PreferencePage implements IWorkb
 			if (cachedElements == null) {
 				Object[] children = super.fetchChildren(o, monitor);
 				cachedElements = new Hashtable<>(children.length);
+				String fragments = System.getProperty("p2.fragments"); //$NON-NLS-1$
 				for (int i = 0; i < children.length; i++) {
 					if (children[i] instanceof MetadataRepositoryElement) {
-						put((MetadataRepositoryElement) children[i]);
+						// Filter out locations that are actually installed p2 droplets
+						if (fragments != null) {
+							boolean isDroplet = false;
+							for (String root : fragments.split(",")) { //$NON-NLS-1$
+								URI childLoc = ((MetadataRepositoryElement) children[i]).getLocation();
+								if (childLoc.getPath() != null && childLoc.getPath().startsWith(root)) {
+									isDroplet = true;
+								}
+							}
+							if (!isDroplet) {
+								put((MetadataRepositoryElement) children[i]);
+							}
+						}
 					}
 				}
 			}