The Vietnamese market (Bloomberg) were up about 0.5%, but the VNM ETF was down over 1%. It could have been currency-related since any foreign stock is both a stock and currency position rolled into one.
The Vietnamese market was even last night, so we'll see what happens tommorow.
When I do sell VNM, it is not as important that I am watching the market all day to get the best price because most of the move in foreign stocks (ADRs) and foreign ETFs that trade in the U.S. will be a result of their moves the foreign market. The American shares are simply pricing in the (dollar-adjusted) move that the stock made in its home market overnight. Consequently, most of this move comes at the open, and the range after the first half hour will be very tight. The most common pattern is a big gap at the open and then trading sideways the rest of the day, like in the chart below of VNM over the last few days.

This is the first pure swing trade I have done in proabbly a couple of years. There have been a few times I have taken a position in stock, but only becuase I had options that I had written that were excersized by the buyer. I don't want to spend too much time in this trade because I want to get back to my option writing.