Fix issue #460 - Specific messages when a feature is not supported.

app/src/main/java/app/fedilab/android/activities/ComposeActivity.java

@@ -222,6 +222,11 @@ public class ComposeActivity extends BaseActivity implements ComposeAdapter.Mana
 
             });
             alt_bld.setNegativeButton(R.string.no, (dialog, id) -> {
+                try {
+                    new StatusDraft(ComposeActivity.this).removeDraft(statusDraft);
+                } catch (DBException e) {
+                    e.printStackTrace();
+                }
                 dialog.dismiss();
                 finish();
             });

app/src/main/java/app/fedilab/android/activities/FollowedTagActivity.java

@@ -145,7 +145,7 @@ public class FollowedTagActivity extends BaseActivity implements FollowedTagAdap
                                     tagList.add(0, newTag);
                                     followedTagAdapter.notifyItemInserted(0);
                                 } else {
-                                    Toasty.error(FollowedTagActivity.this, getString(R.string.toast_error), Toasty.LENGTH_LONG).show();
+                                    Toasty.error(FollowedTagActivity.this, getString(R.string.toast_feature_not_supported), Toasty.LENGTH_LONG).show();
                                 }
                             });
                     dialog.dismiss();

app/src/main/res/values/strings.xml

@@ -1985,4 +1985,5 @@
     <string name="follow_tag">Follow tag</string>
     <string name="action_lists_edit">Edit list</string>
     <string name="profiles">Profiles</string>
+    <string name="toast_feature_not_supported">Your instance does not seem to support that feature!</string>
 </resources>