Erase elements after removing them from ROI vector

When computing the vector containing the detectors to ROI, in the
case of pixel and tube, erase elements after using remove, both to
remove a warning and because it is not supposed to work without this
change, even though it did.

qt/widgets/instrumentview/src/InstrumentWidgetMaskTab.cpp

@@ -581,8 +581,11 @@ void InstrumentWidgetMaskTab::singlePixelPicked(size_t pickID) {
 
     if (m_pixel->isChecked()) {
       // remove the picked pixel from the list of detectors to mask
-      std::remove(detectorsToMask.begin(), detectorsToMask.end(), pickID);
+      std::vector<size_t>::iterator newEnd;
 
+      newEnd =
+          std::remove(detectorsToMask.begin(), detectorsToMask.end(), pickID);
+      detectorsToMask.erase(newEnd, detectorsToMask.end());
     } else if (m_tube->isChecked()) {
       if (!componentInfo.hasParent(pickID)) {
         return;
@@ -592,9 +595,11 @@ void InstrumentWidgetMaskTab::singlePixelPicked(size_t pickID) {
 
       // remove all the detectors from the picked tube from the list of
       // detectors to mask
+      std::vector<size_t>::iterator newEnd = detectorsToMask.end();
       for (auto toKeep : detectorsToKeep) {
-        std::remove(detectorsToMask.begin(), detectorsToMask.end(), toKeep);
+        newEnd = std::remove(detectorsToMask.begin(), newEnd, toKeep);
       }
+      detectorsToMask.erase(newEnd, detectorsToMask.end());
     }
     // then mask selected detectors
     actor.addMaskBinsData(detectorsToMask);