fix: fix re-import hidden custom token with checksum address

[sahar-fehri]

Description

When a user re-imports a hidden token using custom import with checksum address, the token fails to import.
The test works successfully using the search token feature or adding the custom token in lowercase format.

The search token feature sends the tokens to the addTokens function in core in lowercase format because the tokensChainsCache in state are also in lowercase format.

When the user tries to re-add a hidden token in a checksum format; this causes the filter on this line to fail; hence the token does not appear on the list after clicking import.

The fix makes the addresses sent to the addTokens fct in lowercase to match the casing of tokensChainsCache.

Changelog

CHANGELOG entry: Fixed a bug that was causing re-importing a previously hidden token using custom appear to not appear in the list

Related issues

Fixes: #36559

Manual testing steps

1. Click on import tokens
2. Import any token from search
3. Notice the token is visible in the tokenList
4. Click on the imported token
5. Copy the checksummed token address from the asset details page
6. Click on the options button and Hide the token
7. Click on import tokens and click on custom
8. Input the checksummed token address and click on import
9. You should see the token visible in the list

Screenshots/Recordings

Before

Screen.Recording.2025-10-10.at.16.39.39.mov

After

Screen.Recording.2025-10-10.at.16.42.32.mov

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

---

Note

Lowercases addresses of imported tokens in addImportedTokens before sending to background.

^{Written by Cursor Bugbot for commit 53da464. This will update automatically on new commits. Configure here.}

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[metamaskbot]

📊 Page Load Benchmark Results

Current Commit: 6765478 | Date: 10/10/2025

📄 Localhost MetaMask Test Dapp

Samples: 100

Summary

• pageLoadTime-> current mean value: 1.05s (±74ms) 🟡 | historical mean value: 1.05s ⬆️ (historical data)
• domContentLoaded-> current mean value: 736ms (±72ms) 🟢 | historical mean value: 737ms ⬇️ (historical data)
• firstContentfulPaint-> current mean value: 76ms (±12ms) 🟢 | historical mean value: 80ms ⬇️ (historical data)

📈 Detailed Results

Metric	Mean	Std Dev	Min	Max	P95	P99
pageLoadTime	1.05s	74ms	1.01s	1.34s	1.29s	1.34s
domContentLoaded	736ms	72ms	700ms	1.02s	970ms	1.02s
firstPaint	76ms	12ms	60ms	180ms	84ms	180ms
firstContentfulPaint	76ms	12ms	60ms	180ms	84ms	180ms
largestContentfulPaint	0ms	0ms	0ms	0ms	0ms	0ms

---

Results generated automatically by MetaMask CI

[metamaskbot]

Builds ready [6765478]

• builds: chrome, firefox
• builds (beta): chrome, firefox
• builds (flask): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• bundle size: Bundle Size Stats
• user-actions-benchmark: User Actions Stats
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6, 7, 8
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
  • ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
  • content-script: 0
  • offscreen: 0

UI Startup Metrics (1248 ± 68 ms)

Platform	BuildType	Page	Metric	Mean (ms)	Min (ms)	Max (ms)	Std Dev (ms)	P 75 (ms)	P 95 (ms)
Chrome	Browserify	Home	uiStartup	1248	1109	1434	68	1285	1368
			load	1073	934	1264	63	1111	1201
			domContentLoaded	1065	930	1258	65	1107	1197
			domInteractive	17	14	42	5	17	31
			firstPaint	735	79	1270	428	1087	1164
			backgroundConnect	260	244	370	16	261	277
			firstReactRender	26	17	75	8	27	42
			getState	13	4	82	10	14	30
			initialActions	7	0	37	8	7	31
			loadScripts	813	678	1008	64	850	939
			setupStore	9	5	26	3	10	17
	Webpack	Home	uiStartup	802	690	1043	60	822	939
			load	618	571	894	60	626	782
			domContentLoaded	610	566	887	60	618	776
			domInteractive	14	11	43	6	13	32
			firstPaint	192	57	892	187	187	590
			backgroundConnect	21	10	40	6	25	32
			firstReactRender	27	16	139	13	30	33
			getState	8	3	18	3	10	12
			initialActions	2	0	12	2	3	6
			loadScripts	607	564	874	58	616	762
			setupStore	8	4	18	2	8	11
Firefox	Browserify	Home	uiStartup	1388	1180	1895	126	1482	1600
			load	1195	1025	1470	100	1272	1364
			domContentLoaded	1195	1024	1470	100	1272	1364
			domInteractive	100	34	298	51	107	219
			firstPaint	NaN	NaN	NaN	NaN	NaN	NaN
			backgroundConnect	29	18	111	14	32	47
			firstReactRender	29	25	49	4	30	37
			getState	6	3	63	7	5	14
			initialActions	3	0	28	5	2	16
			loadScripts	1172	1006	1440	96	1246	1341
			setupStore	9	4	119	13	7	30
	Webpack	Home	uiStartup	1568	1376	2110	148	1608	1974
			load	1354	1200	1680	99	1414	1559
			domContentLoaded	1354	1200	1680	99	1414	1559
			domInteractive	96	33	378	51	103	176
			firstPaint	NaN	NaN	NaN	NaN	NaN	NaN
			backgroundConnect	34	19	141	20	38	96
			firstReactRender	35	27	82	10	37	47
			getState	7	2	48	9	6	29
			initialActions	5	0	135	15	2	23
			loadScripts	1329	1184	1574	93	1394	1531
			setupStore	14	4	145	22	8	58

Bundle size diffs [🚀 Bundle size reduced!]

• background: -7.61 KiB (-0.17%)
• ui: 1.48 KiB (0.02%)
• common: 197 Bytes (0%)

[metamaskbot]

📊 Page Load Benchmark Results

Current Commit: b9488f5 | Date: 10/10/2025

📄 Localhost MetaMask Test Dapp

Samples: 100

Summary

• pageLoadTime-> current mean value: 1.04s (±72ms) 🟡 | historical mean value: 1.05s ⬇️ (historical data)
• domContentLoaded-> current mean value: 731ms (±69ms) 🟢 | historical mean value: 737ms ⬇️ (historical data)
• firstContentfulPaint-> current mean value: 76ms (±11ms) 🟢 | historical mean value: 80ms ⬇️ (historical data)

📈 Detailed Results

Metric	Mean	Std Dev	Min	Max	P95	P99
pageLoadTime	1.04s	72ms	1.00s	1.32s	1.29s	1.32s
domContentLoaded	731ms	69ms	694ms	995ms	975ms	995ms
firstPaint	76ms	11ms	56ms	160ms	88ms	160ms
firstContentfulPaint	76ms	11ms	56ms	160ms	88ms	160ms
largestContentfulPaint	0ms	0ms	0ms	0ms	0ms	0ms

---

Results generated automatically by MetaMask CI

[metamaskbot]

Builds ready [b9488f5]

• builds: chrome, firefox
• builds (beta): chrome, firefox
• builds (flask): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• bundle size: Bundle Size Stats
• user-actions-benchmark: User Actions Stats
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6, 7, 8
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
  • ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
  • content-script: 0
  • offscreen: 0

UI Startup Metrics (1250 ± 83 ms)

Platform	BuildType	Page	Metric	Mean (ms)	Min (ms)	Max (ms)	Std Dev (ms)	P 75 (ms)	P 95 (ms)
Chrome	Browserify	Home	uiStartup	1250	1111	1590	83	1280	1442
			load	1081	942	1439	82	1109	1275
			domContentLoaded	1073	936	1432	82	1101	1268
			domInteractive	19	14	122	12	17	39
			firstPaint	706	76	1441	442	1088	1163
			backgroundConnect	254	241	288	9	258	273
			firstReactRender	27	19	179	17	25	48
			getState	11	5	30	6	14	25
			initialActions	4	0	28	4	5	11
			loadScripts	826	690	1195	82	850	1013
			setupStore	9	6	36	4	9	15
	Webpack	Home	uiStartup	808	696	1082	68	828	991
			load	623	574	925	69	625	832
			domContentLoaded	615	569	916	68	619	827
			domInteractive	15	11	50	7	13	35
			firstPaint	176	56	881	174	188	591
			backgroundConnect	21	10	49	6	25	30
			firstReactRender	26	16	57	7	31	35
			getState	8	4	16	3	9	12
			initialActions	2	0	9	2	3	6
			loadScripts	612	567	905	66	617	813
			setupStore	8	4	18	2	9	12
Firefox	Browserify	Home	uiStartup	1420	1192	1800	128	1498	1701
			load	1217	1034	1419	91	1305	1374
			domContentLoaded	1217	1034	1419	91	1305	1374
			domInteractive	98	33	319	51	105	221
			firstPaint	NaN	NaN	NaN	NaN	NaN	NaN
			backgroundConnect	31	19	112	15	33	68
			firstReactRender	29	25	53	4	31	38
			getState	8	2	267	26	5	17
			initialActions	4	0	139	15	2	14
			loadScripts	1193	1016	1390	89	1276	1351
			setupStore	12	4	148	23	6	60
	Webpack	Home	uiStartup	1548	1353	2025	126	1598	1801
			load	1339	1200	1636	90	1378	1538
			domContentLoaded	1338	1199	1635	90	1377	1538
			domInteractive	98	30	370	70	97	357
			firstPaint	NaN	NaN	NaN	NaN	NaN	NaN
			backgroundConnect	32	19	125	15	36	61
			firstReactRender	38	26	85	15	37	78
			getState	9	2	125	16	6	43
			initialActions	5	0	120	15	2	25
			loadScripts	1313	1180	1608	88	1359	1493
			setupStore	11	4	66	13	8	48

Bundle size diffs [🚀 Bundle size reduced!]

• background: -7.61 KiB (-0.17%)
• ui: 1.48 KiB (0.02%)
• common: 203 Bytes (0%)

[metamaskbot]

📊 Page Load Benchmark Results

Current Commit: 53da464 | Date: 10/10/2025

📄 Localhost MetaMask Test Dapp

Samples: 100

Summary

• pageLoadTime-> current mean value: 1.04s (±73ms) 🟡 | historical mean value: 1.05s ⬇️ (historical data)
• domContentLoaded-> current mean value: 731ms (±70ms) 🟢 | historical mean value: 738ms ⬇️ (historical data)
• firstContentfulPaint-> current mean value: 77ms (±14ms) 🟢 | historical mean value: 81ms ⬇️ (historical data)

📈 Detailed Results

Metric	Mean	Std Dev	Min	Max	P95	P99
pageLoadTime	1.04s	73ms	1.00s	1.31s	1.29s	1.31s
domContentLoaded	731ms	70ms	695ms	1.00s	967ms	1.00s
firstPaint	77ms	14ms	60ms	196ms	88ms	196ms
firstContentfulPaint	77ms	14ms	60ms	196ms	88ms	196ms
largestContentfulPaint	0ms	0ms	0ms	0ms	0ms	0ms

---

Results generated automatically by MetaMask CI

[metamaskbot]

Builds ready [53da464]

• builds: chrome, firefox
• builds (beta): chrome, firefox
• builds (flask): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• bundle size: Bundle Size Stats
• user-actions-benchmark: User Actions Stats
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6, 7, 8
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
  • ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
  • content-script: 0
  • offscreen: 0

UI Startup Metrics (1273 ± 63 ms)

Platform	BuildType	Page	Metric	Mean (ms)	Min (ms)	Max (ms)	Std Dev (ms)	P 75 (ms)	P 95 (ms)
Chrome	Browserify	Home	uiStartup	1273	1134	1425	63	1309	1403
			load	1090	983	1227	57	1122	1202
			domContentLoaded	1083	977	1221	56	1117	1196
			domInteractive	19	14	88	9	18	36
			firstPaint	687	85	1223	435	1093	1188
			backgroundConnect	258	243	409	17	262	272
			firstReactRender	27	19	127	12	27	44
			getState	13	5	80	11	15	29
			initialActions	5	0	25	4	5	15
			loadScripts	832	724	964	55	863	951
			setupStore	9	6	24	3	10	17
	Webpack	Home	uiStartup	783	663	1000	65	818	893
			load	605	542	848	75	625	756
			domContentLoaded	596	535	840	74	620	747
			domInteractive	16	11	63	8	14	33
			firstPaint	183	52	832	181	165	704
			backgroundConnect	22	10	45	7	27	34
			firstReactRender	25	16	54	8	30	36
			getState	8	3	28	4	9	14
			initialActions	2	0	9	2	3	7
			loadScripts	594	533	830	73	618	745
			setupStore	7	4	18	2	9	12
Firefox	Browserify	Home	uiStartup	1450	1269	2114	130	1500	1673
			load	1229	1098	1405	82	1287	1370
			domContentLoaded	1228	1097	1404	82	1286	1370
			domInteractive	101	36	296	52	105	241
			firstPaint	NaN	NaN	NaN	NaN	NaN	NaN
			backgroundConnect	31	20	134	15	34	61
			firstReactRender	31	26	56	5	32	45
			getState	8	3	92	12	6	29
			initialActions	5	0	186	19	2	14
			loadScripts	1206	1079	1377	80	1261	1349
			setupStore	11	4	132	18	7	59
	Webpack	Home	uiStartup	1529	1330	2135	131	1579	1770
			load	1330	1184	1776	96	1381	1488
			domContentLoaded	1330	1183	1775	96	1381	1488
			domInteractive	96	29	423	57	101	236
			firstPaint	NaN	NaN	NaN	NaN	NaN	NaN
			backgroundConnect	30	17	109	16	33	67
			firstReactRender	34	26	82	10	37	72
			getState	8	2	152	16	5	41
			initialActions	3	0	61	7	2	13
			loadScripts	1306	1166	1747	92	1352	1466
			setupStore	11	3	109	16	7	46

Bundle size diffs [🚨 Warning! Bundle size has increased!]

• background: 58 Bytes (0%)
• ui: 0 Bytes (0%)
• common: 69 Bytes (0%)