Neither did Ephraim - See the notes on the parallel passages, Joshua 16:5-10 (note).

Neither did Ephraim drive out the Canaanites that dwelt in Gezer,.... Not so much as made them tributaries, but made a covenant with them, it is probable, contrary to the express will of God:

but the Canaanites dwelt in Gezer among them; the Ephraimites agreeing to it, and here they dwelt to the times of Solomon; See Gill on Joshua 16:10; where indeed they are said to be under tribute; but that seems to respect some later time, and not when they were first admitted to dwell among them, since no mention is made of it here.

Ephraim did not root out the Canaanites in Gezer (Judges 1:29), as has already been stated in Joshua 16:10.

Neither did Ephraim drive out the Canaanites that dwelt in Gezer; but the Canaanites dwelt in Gezer among them.

1:29 In Gezer - Which they possessed 'till Solomon's time, 1Kings 9:16.

1:21-36 The people of Israel were very careless of their duty and interest. Owing to slothfulness and cowardice, they would not be at the pains to complete their conquests. It was also owing to their covetousness: they were willing to let the Canaanites live among them, that they might make advantage of them. They had not the dread and detestation of idolatry they ought to have had. The same unbelief that kept their fathers forty years out of Canaan, kept them now out of the full possession of it. Distrust of the power and promise of God deprived them of advantages, and brought them into troubles. Thus many a believer who begins well is hindered. His graces languish, his lusts revive, Satan plies him with suitable temptations, the world recovers its hold; he brings guilt into his conscience, anguish into his heart, discredit on his character, and reproach on the gospel. Though he may have sharp rebukes, and be so recovered that he does not perish, yet he will have deeply to lament his folly through his remaining days; and upon his dying bed to mourn over the opportunities of glorifying God and serving the church he has lost. We can have no fellowship with the enemies of God within us or around us, but to our hurt; therefore our only wisdom is to maintain unceasing war against them.