[ui-controls] make sure that posframe is workable

Fixes #409

Author: yyoncho

dap-ui.el

@@ -501,50 +501,51 @@ DEBUG-SESSION is the debug session triggering the event."
               'help-echo hover-text))
 
 (defun dap-ui--update-controls (&rest _)
-  (let* ((session (dap--cur-session))
-         (stopped? (and session (dap--debug-session-active-frame session)))
-         (running? (and session (dap--session-running session))))
-    (if running?
-        (let ((content (s-concat
-                        (dap-ui--create-command "continue.png" #'dap-continue "Continue")
-                        " "
-                        (dap-ui--create-command (if stopped?
-                                                    "step-over.png"
-                                                  "step-over-disabled.png")
-                                                (when stopped? #'dap-next)
-                                                (if stopped? "Step over"
-                                                  "Session not stopped?"))
-                        " "
-                        (dap-ui--create-command (if stopped? "step-out.png"
-                                                  "step-out-disabled.png")
-                                                (when stopped? #'dap-step-out)
-                                                (if stopped? "Step out"
-                                                  "Session not stopped? "))
-                        " "
-                        (dap-ui--create-command (if stopped? "step-into.png"
-                                                  "step-into-disabled.png")
-                                                (when stopped? #'dap-step-in)
-                                                (if stopped? "Step in"
-                                                  "Session not stopped?"))
-                        " "
-                        (dap-ui--create-command "disconnect.png" #'dap-disconnect "Disconnect")
-                        " "
-                        (dap-ui--create-command "restart.png" #'dap-debug-restart "Restart")))
-              posframe-mouse-banish
-              (pos-frame (-first
-                          (lambda (frame)
-                            (let ((buffer-info (frame-parameter frame 'posframe-buffer)))
-                              (or (equal dap-ui--control-buffer (car buffer-info))
-                                  (equal dap-ui--control-buffer (cdr buffer-info)))))
-                          (frame-list))))
-          (ignore posframe-mouse-banish)
-          (when (eq (selected-frame) pos-frame)
-            (select-frame (frame-parent pos-frame)))
-          (posframe-show dap-ui--control-buffer
-                         :string content
-                         :poshandler #'posframe-poshandler-frame-top-center
-                         :internal-border-width 8))
-      (posframe-hide dap-ui--control-buffer))))
+  (when (posframe-workable-p)
+    (let* ((session (dap--cur-session))
+           (stopped? (and session (dap--debug-session-active-frame session)))
+           (running? (and session (dap--session-running session))))
+      (if running?
+          (let ((content (s-concat
+                          (dap-ui--create-command "continue.png" #'dap-continue "Continue")
+                          " "
+                          (dap-ui--create-command (if stopped?
+                                                      "step-over.png"
+                                                    "step-over-disabled.png")
+                                                  (when stopped? #'dap-next)
+                                                  (if stopped? "Step over"
+                                                    "Session not stopped?"))
+                          " "
+                          (dap-ui--create-command (if stopped? "step-out.png"
+                                                    "step-out-disabled.png")
+                                                  (when stopped? #'dap-step-out)
+                                                  (if stopped? "Step out"
+                                                    "Session not stopped? "))
+                          " "
+                          (dap-ui--create-command (if stopped? "step-into.png"
+                                                    "step-into-disabled.png")
+                                                  (when stopped? #'dap-step-in)
+                                                  (if stopped? "Step in"
+                                                    "Session not stopped?"))
+                          " "
+                          (dap-ui--create-command "disconnect.png" #'dap-disconnect "Disconnect")
+                          " "
+                          (dap-ui--create-command "restart.png" #'dap-debug-restart "Restart")))
+                posframe-mouse-banish
+                (pos-frame (-first
+                            (lambda (frame)
+                              (let ((buffer-info (frame-parameter frame 'posframe-buffer)))
+                                (or (equal dap-ui--control-buffer (car buffer-info))
+                                    (equal dap-ui--control-buffer (cdr buffer-info)))))
+                            (frame-list))))
+            (ignore posframe-mouse-banish)
+            (when (eq (selected-frame) pos-frame)
+              (select-frame (frame-parent pos-frame)))
+            (posframe-show dap-ui--control-buffer
+                           :string content
+                           :poshandler #'posframe-poshandler-frame-top-center
+                           :internal-border-width 8))
+        (posframe-hide dap-ui--control-buffer)))))
 
 ;;;###autoload
 (define-minor-mode dap-ui-controls-mode