Third-party glyphs break the set
Aliases: third-party icons · imported glyph · mixed icon libraries
What it is
When a missing drawing is dragged in from another library, that one glyph speaks in its own voice: different grid, different optical centre, different counters. The usual problem is not the wrong subject. It is that an undeclared drafting method has entered the row. Users need not be able to name the other library to feel that this item is not from the house.
Why it happens
Every icon family seats its skeleton on an implicit grid: some geometric, some optically compensated, some with larger interior gaps. The imported path can have its stroke forced to a nearby number and still breathe on the old family's rhythm. During a scan it jumps — tighter, floatier, or anchored high. That jump is logged as "this one is special", so a peer entry collects unearned attention, or looks like a broken control. Tracing the stroke to match weight only skins the path; the skeleton remains. The break happens when the host grid is never recomputed.
Where it stops holding
- Platform system symbols are not third-party inside that platform's own apps. Moved into a custom-drawn toolbar, they become third-party.
- A foreign subject that has been redrawn onto the host grid is no longer an import. The test is the grid, not the inspiration.
- File-type badges, payment marks, and brand logos have legal or recognition-critical outlines and must not be restyled past recognition. Isolate them in content; keep them out of the nav parameter set.
- This is a foreign drafting method in the same row, not whether the house table was written, and not the outline/filled state grammar.
Applying it
- When a glyph is missing, redraw it on the host grid before it ships. Borrow subject matter from a library, not paths.
- For imports already in place, re-anchor optical centre and counters to the host grid. Do not stop at restroking.
- How to check: swap the foreign glyph with a neighbour in the toolbar. If it jumps in every slot, the drafting method is the source, not the importance of that function.