use grey theme if no theming of elements is possible

src/main/java/com/owncloud/android/ui/dialog/ExpirationDatePickerDialogFragment.java

@@ -23,7 +23,6 @@ package com.owncloud.android.ui.dialog;
 
 import android.app.DatePickerDialog;
 import android.app.Dialog;
-import android.content.DialogInterface;
 import android.os.Bundle;
 import android.support.v4.app.DialogFragment;
 import android.text.format.DateUtils;
@@ -31,7 +30,6 @@ import android.widget.DatePicker;
 
 import com.owncloud.android.datamodel.OCFile;
 import com.owncloud.android.ui.activity.FileActivity;
-import com.owncloud.android.utils.DisplayUtils;
 
 import java.util.Calendar;
 
@@ -71,17 +69,6 @@ public class ExpirationDatePickerDialogFragment
         return dialog;
     }
 
-    @Override
-    public void onStart() {
-        super.onStart();
-
-        int accentColor = DisplayUtils.primaryAccentColor();
-
-        DatePickerDialog dialog = (DatePickerDialog) getDialog();
-        dialog.getButton(DialogInterface.BUTTON_POSITIVE).setTextColor(accentColor);
-        dialog.getButton(DialogInterface.BUTTON_NEGATIVE).setTextColor(accentColor);
-    }
-
     /**
      * {@inheritDoc}
      *

src/main/java/com/owncloud/android/ui/fragment/ShareFileFragment.java

@@ -192,6 +192,11 @@ public class ShareFileFragment extends Fragment implements ShareUserListAdapter.
                              Bundle savedInstanceState) {
         Log_OC.d(TAG, "onCreateView");
 
+        // use grey as fallback for elements where custom theming is not available
+        if (DisplayUtils.themingEnabled()) {
+            getContext().getTheme().applyStyle(R.style.FallbackThemingTheme, true);
+        }
+
         int accentColor = DisplayUtils.primaryAccentColor();
 
         // Inflate the layout for this fragment
@@ -740,7 +745,7 @@ public class ShareFileFragment extends Fragment implements ShareUserListAdapter.
 
             // GetLink button
             AppCompatButton getLinkButton = getGetLinkButton();
-            getLinkButton.getBackground().setColorFilter(DisplayUtils.primaryAccentColor(), PorterDuff.Mode.DST_ATOP);
+            getLinkButton.getBackground().setColorFilter(DisplayUtils.primaryAccentColor(), PorterDuff.Mode.SRC_ATOP);
             getLinkButton.setVisibility(View.VISIBLE);
             getLinkButton.setOnClickListener(new View.OnClickListener() {
                 @Override

src/main/java/com/owncloud/android/ui/fragment/contactsbackup/ContactsBackupFragment.java

@@ -105,6 +105,7 @@ public class ContactsBackupFragment extends FileFragment implements DatePickerDi
     @Override
     public View onCreateView(final LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
 
+        // use grey as fallback for elements where custom theming is not available
         if (DisplayUtils.themingEnabled()) {
             getContext().getTheme().applyStyle(R.style.FallbackThemingTheme, true);
         }