Index: trunk/src/org/openstreetmap/josm/gui/preferences/imagery/AddWMSLayerPanel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/preferences/imagery/AddWMSLayerPanel.java	(revision 17541)
+++ trunk/src/org/openstreetmap/josm/gui/preferences/imagery/AddWMSLayerPanel.java	(revision 17543)
@@ -30,4 +30,5 @@
 import org.openstreetmap.josm.tools.GBC;
 import org.openstreetmap.josm.tools.Logging;
+import org.openstreetmap.josm.tools.Utils;
 
 /**
@@ -83,5 +84,5 @@
         getLayers.addActionListener(e -> {
             try {
-                wms = new WMSImagery(rawUrl.getText(), getCommonHeaders());
+                wms = new WMSImagery(Utils.strip(rawUrl.getText()), getCommonHeaders());
                 tree.updateTree(wms);
                 Collection<String> wmsFormats = wms.getFormats();
Index: trunk/src/org/openstreetmap/josm/gui/preferences/imagery/AddWMTSLayerPanel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/preferences/imagery/AddWMTSLayerPanel.java	(revision 17541)
+++ trunk/src/org/openstreetmap/josm/gui/preferences/imagery/AddWMTSLayerPanel.java	(revision 17543)
@@ -24,4 +24,5 @@
 import org.openstreetmap.josm.tools.GBC;
 import org.openstreetmap.josm.tools.Logging;
+import org.openstreetmap.josm.tools.Utils;
 
 /**
@@ -61,5 +62,5 @@
         getLayers.addActionListener(e -> {
             try {
-                WMTSCapabilities capabilities = WMTSTileSource.getCapabilities(rawUrl.getText(), getCommonHeaders());
+                WMTSCapabilities capabilities = WMTSTileSource.getCapabilities(Utils.strip(rawUrl.getText()), getCommonHeaders());
                 layerTable = new WMTSLayerSelection(WMTSTileSource.groupLayersByNameAndTileMatrixSet(capabilities.getLayers()));
                 layerTable.getTable().getSelectionModel().addListSelectionListener(lsl -> {