Encountering issues with std::mutex and std::thread - c++

Question

I am encountering issues with both std::thread and std::mutex, unable to get both to play nicely with each other. I've been pulling my hair out over this for the past few hours and just cannot make any progress whatsoever. I believe it is out of my skill area. The code is just below:
void GekkoFyre::TuiHangouts::gui_userRosterListNav(std::shared_ptr<WINDOW> display,
std::vector<const char *> userList,
const short &menuItem)
{
while (rosterEnabled) {
for (short i = 0; i < totalMenuItems; ++i) {
short diff = (menuItem - i);
if (i < numMenuItems) {
if (i == menuItem) {
size_t msgLen = strlen(userList.at(i));
size_t l = 0;
if (msgLen > subMaxX) {
for (l = subMaxX; l < msgLen; ++l) {
// Scroll the message from left to right, then vice versa, so that it fits within
// the designated window.
std::this_thread::sleep_for(std::chrono::milliseconds(500));
rosterListMutex.lock();
wattron(usrSubWin.get(), A_REVERSE); // Highlight selection
const char *msg = userList.at(i);
mvwaddstr(usrSubWin.get(), i, 0, &msg[(msgLen - l)]);
wrefresh(usrSubWin.get());
touchwin(usrSubWin.get());
rosterListMutex.unlock();
}
} else {
rosterListMutex.lock();
wattron(usrSubWin.get(), A_REVERSE); // Highlight selection
mvwaddstr(usrSubWin.get(), i, 0, userList.at(i));
wrefresh(usrSubWin.get());
touchwin(usrSubWin.get());
rosterListMutex.unlock();
}
}
wattroff(usrSubWin.get(), A_REVERSE); // Remove highlight
if ((i + 1) < numMenuItems) {
mvwaddstr(usrSubWin.get(), (i + 1), 0, userList.at((i + 1)));
}
} else if (diff < (totalMenuItems - numMenuItems) && diff > 0) {
// Allow the scrolling of a username list, from downwards and then back upwards, so that
// the user may see the list in its entirety.
wclear(usrSubWin.get());
int pos = 0;
for (short c = diff; c < (numMenuItems + diff); ++c) {
++pos;
mvwaddstr(usrSubWin.get(), pos, 0, userList.at(c));
}
pos = 0;
break;
}
}
rosterListMutex.lock();
wattroff(usrSubWin.get(), A_REVERSE); // Remove highlight
touchwin(usrSubWin.get());
wrefresh(usrSubWin.get());
wrefresh(display.get());
rosterListMutex.unlock();
}
}
I am trying to display a list of users to the left of a chat window in NCurses, as can be seen in [ 1 ] below, albeit without any users present in said screenshot. I want to keep my privacy :) What happens is that as you scroll down the list, flickering begins to occur back and forth between two usernames after scrolling past just a few. They keep repeatedly selecting each other, just over and over. I believe this is reason of the threads not syncing up properly. The function is implemented as so:
[ 1 ] - http://imgur.com/ZZlFHg2
#define WIDGET_USERS_LIST 1
short menuItem = 0;
int ch = 0;
int curr_widget = 0;
std::thread rosterListNav1(&GekkoFyre::TuiHangouts::gui_userRosterListNav, this, userListWin, rosterFormatted, menuItem);
rosterListNav1.detach();
while ((ch = wgetch(display.get())) != KEY_F(12)) {
switch (ch) {
case KEY_DOWN:
if (curr_widget == WIDGET_USERS_LIST && rosterEnabled) {
++menuItem;
if (menuItem > totalMenuItems - 1) {
menuItem = 0;
}
}
break;
case KEY_UP:
if (curr_widget == WIDGET_USERS_LIST && rosterEnabled) {
--menuItem;
if (menuItem < 0) {
menuItem = totalMenuItems - 1;
}
}
}
std::thread rosterListNav2(&GekkoFyre::TuiHangouts::gui_userRosterListNav, this, userListWin, rosterFormatted, menuItem);
rosterListNav2.detach();
}
Any help on this issue would be dearly appreciated, and I believe I have placed the std::mutex's in the right areas. I am really stumped with this problem. Also beware that while I know a few tricks of the trade, I am entirely self-taught. Some of the nomenclature that is normal to programmers who have gone through university is completely unintelligible to me.