A partial close lets a trader close only a portion of an open position's size, locking in some profit (or cutting some risk) while leaving the remainder running. It's commonly used to bank gains at a first target while letting the rest of the position ride toward a further take-profit level.
After a partial close, many traders also move the stop-loss on the remaining portion to break-even, so the trade can no longer turn into a net loss even if the market reverses.
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Guide
Why a Signal Disappears Before the Bar Closes
The right-most bar is still being built, so everything drawn from it is provisional. What redraws honestly, what confirmation costs, and which setting decides what you are looking at.