Created attachment 187556 [details] streched arrow Symblo of widevec and wideharpoon are stretched evenly when they become wider, but the arrowhead shouldn't be stretched, like what they do in latex ：）
Technically this is not a bug, rather an enhancement. As with bug 32362 for scaling or stretching of vertical bracketing, sm formula "nodes" are calculated in width and size for the formula, and then currently a *single* glyph is stretched to fit. For Starmath's vec/widevec the glyph is U+20D7 "COMBINING RIGHT ARROW ABOVE" We added support for a single glyph harpoon for bug 120047, harpoon/wideharpoon using U+20D1 "COMBINING RIGHT HARPOON ABOVE" However to do better stretching, the need is to compose sm "nodes" with multi-glyph strings. For the wideharpoon and the widevec that might be using the arrow heads with the U+23AF unicode. And maybe similar with U+23D0 for vertical arrows. While using the the 2 and 3 glyph brackets sets-- TOP, BOTTOM / LEFT, RIGHT and the EXTENSION (HORIZONTAL, VERTICAL) as for bug 32362. Of course few of these Unicode points are defined in our OpenSymbol font set so the appropriate gylyphs would need to be added once the Starmath module logic is refactored to support multi-glyph brackets and arrows.
*** This bug has been marked as a duplicate of bug 32362 ***