#671 added wrong perspective as a hint to root cause

Author: jantje

io.sloeber.ui/src/io/sloeber/ui/messages.properties

@@ -1,6 +1,6 @@
 error_adding_arduino_code=Error adding the arduino code
 error_no_platform_files_found=No platform files found: This should never happen
-error_no_Arduino_project_selected=There are no projects selected or all selected projects are not arduino projects.
+error_no_Arduino_project_selected=There are no projects selected or all selected projects are not arduino projects. Are you in the Arduino perspective?
 error_no_host_name=No host name provided
 error_failed_to_import_library_in_project=Failed to import library
 json_browser_fail=Failed to start browser.