diff --git a/putty.h b/putty.h
index 606ff178..fc5c2941 100644
--- a/putty.h
+++ b/putty.h
@@ -2137,6 +2137,7 @@ void term_pwron(Terminal *, bool);
 void term_clrsb(Terminal *);
 void term_mouse(Terminal *, Mouse_Button, Mouse_Button, Mouse_Action,
                 int, int, bool, bool, bool);
+void term_cancel_selection_drag(Terminal *);
 void term_key(Terminal *, Key_Sym, wchar_t *, size_t, unsigned int,
               unsigned int);
 void term_lost_clipboard_ownership(Terminal *, int clipboard);
diff --git a/terminal/terminal.c b/terminal/terminal.c
index 923ed03e..ae5e4144 100644
--- a/terminal/terminal.c
+++ b/terminal/terminal.c
@@ -7299,6 +7299,23 @@ void term_mouse(Terminal *term, Mouse_Button braw, Mouse_Button bcooked,
     term_schedule_update(term);
 }
 
+void term_cancel_selection_drag(Terminal *term)
+{
+    /*
+     * In unusual circumstances, a mouse drag might be interrupted by
+     * something that steals the rest of the mouse gesture. An example
+     * is the GTK popup menu appearing. In that situation, we'll never
+     * receive the MA_RELEASE that finishes the DRAGGING state, which
+     * means terminal output could be suppressed indefinitely. Call
+     * this function from the front end in such situations to restore
+     * sensibleness.
+     */
+    if (term->selstate == DRAGGING)
+        term->selstate = NO_SELECTION;
+    term_out(term, false);
+    term_schedule_update(term);
+}
+
 static int shift_bitmap(bool shift, bool ctrl, bool alt, bool *consumed_alt)
 {
     int bitmap = (shift ? 1 : 0) + (alt ? 2 : 0) + (ctrl ? 4 : 0);
diff --git a/unix/window.c b/unix/window.c
index a8e73789..d9d007b4 100644
--- a/unix/window.c
+++ b/unix/window.c
@@ -2162,6 +2162,8 @@ static gboolean button_internal(GtkFrontend *inst, GdkEventButton *event)
     }
 
     if (event->button == 3 && ctrl) {
+        /* Just in case this happened in mid-select */
+        term_cancel_selection_drag(inst->term);
 #if GTK_CHECK_VERSION(3,22,0)
         gtk_menu_popup_at_pointer(GTK_MENU(inst->menu), (GdkEvent *)event);
 #else
diff --git a/windows/window.c b/windows/window.c
index c81755f2..cb9d5b1c 100644
--- a/windows/window.c
+++ b/windows/window.c
@@ -2641,6 +2641,9 @@ static LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
              (conf_get_int(conf, CONF_mouse_is_xterm) == 2))) {
             POINT cursorpos;
 
+            /* Just in case this happened in mid-select */
+            term_cancel_selection_drag(term);
+
             show_mouseptr(true);    /* make sure pointer is visible */
             GetCursorPos(&cursorpos);
             TrackPopupMenu(popup_menus[CTXMENU].menu,