src/DodoSSH.Client.App/Views/SessionSidebar.axaml

@@ -70,12 +70,25 @@
             The address, and the button that closes the column. Both on one row, and the address is the
             trimming one: a long account@host:port is exactly the string that would otherwise push the
             close button off the edge of a panel whose whole point is that it can be got rid of.
+
+            SelectableTextBlock rather than TextBlock, which is what the rest of this application already
+            reaches for whenever a string is on screen to be taken somewhere else — a fingerprint, a public
+            key, a recovery code. This is the one place the shell prints the endpoint it actually dialled,
+            and the endpoint is a thing people paste: into another client, into a ticket, into the ssh
+            command they are writing beside this window. Retyping it off the screen is how a digit gets
+            dropped from an address that is mostly digits.
+
+            The trimming and the selection do disagree at the long end, and the ToolTip is why the
+            disagreement is tolerable rather than a trap: a drag reaches only the glyphs that were drawn,
+            so an address wearing an ellipsis has to be taken with select-all — Ctrl+A, then Ctrl+C — and
+            the hover already shows what the full string is, so nobody is copying half of one without
+            having been told there is a half.
           -->
           <Grid ColumnDefinitions="*,Auto" Margin="8,0,0,0">
-            <TextBlock Grid.Column="0" FontFamily="{StaticResource MonoFont}" FontWeight="Bold"
-                       FontSize="12.5" Foreground="{StaticResource AccentText}"
-                       VerticalAlignment="Center" TextTrimming="CharacterEllipsis"
-                       Text="{Binding SessionAddress}" ToolTip.Tip="{Binding SessionAddress}" />
+            <SelectableTextBlock Grid.Column="0" FontFamily="{StaticResource MonoFont}" FontWeight="Bold"
+                                 FontSize="12.5" Foreground="{StaticResource AccentText}"
+                                 VerticalAlignment="Center" TextTrimming="CharacterEllipsis"
+                                 Text="{Binding SessionAddress}" ToolTip.Tip="{Binding SessionAddress}" />
             <Button Grid.Column="1" Classes="flat sidebargrip"
                     Command="{Binding ToggleSessionSidebarCommand}"
                     ToolTip.Tip="Close this column. The terminal takes the width, and the rail it leaves behind brings it back.">

tests/DodoSSH.Client.App.Layout.Tests/SessionSidebarTests.cs

@@ -128,6 +128,31 @@ public sealed class SessionSidebarTests : IAsyncLifetime
         });
     }
 
+    /// <remarks>
+    /// The address is the one string in this column somebody has to be able to take away with them, and the
+    /// claim under test is the half of that which the trimming could quietly break: an ellipsis is a drawing,
+    /// not a shorter string, so select-all reaches the whole address and not the part that happened to fit.
+    /// Asserted on the longest address this suite has — the case where the two could disagree — rather than
+    /// on one that fits, which would pass whether the trimming were render-only or not.
+    /// </remarks>
+    [Fact]
+    public async Task TheAddressSelectsAndCopiesWholeEvenWhereItIsTrimmed()
+    {
+        await OnTheSidebarAsync((sidebar, _) =>
+        {
+            // Single rather than First: this column prints exactly one string that is there to be copied, and
+            // a second selectable one appearing beside it is a question this test should ask rather than skip.
+            var address = sidebar.GetVisualDescendants().OfType<SelectableTextBlock>().Single();
+
+            address.Text.ShouldBe(LongAddress);
+
+            address.SelectAll();
+
+            address.SelectedText.ShouldBe(LongAddress);
+            address.CanCopy.ShouldBeTrue("Ctrl+C and the right-click Copy item are both gated on this");
+        });
+    }
+
     /// <remarks>
     /// Closed, the control is still drawn and is still the thing the window asks for a width — see
     /// <c>MainWindow.axaml</c>'s own "Auto" column. What it must not be is nothing: a rail with the way back