LinearRegionItem currently fires sigRegionChanged three times when setRegion is used. This seems to be due to the blockLineSignal flag being cleared too early.

I propose to move the flag lower down to fix this - in my testing this results in the signal being fired once instead of thrice.

Minimal code that reproduces this issue in pyqtgraph-0.13.7:

import pyqtgraph as pg
w = pg.PlotWidget()
w.show()
w.plotItem.addItem(region := pg.LinearRegionItem())
region.sigRegionChanged.connect(lambda: print("fired"))
region.setRegion((2, 3))