The red box around the current line in the tracer is not shown until you hit ED or TC in the tracer

[dyaandys]

  ⎕fx'foo' '1' '2' '3'
  foo TC

no red box around foo[1] ER red box around foo[2]

May be mistaken, but I think this used to work ..

IDE: Version: 4.0.2853 Platform: Win32 Date: 2017-07-27 10:42:05 +0100 Git commit: e3f8266860ee9cdae1df12f8651dccca0dacf9c3 Preferences:{ "favs":"[{\"type\":\"connect\",\"ssh_auth_type\":\"pass\",\"ssh_tnl_auth_type\":\"pass\",\"name\":\"debian7dev\",\"host\":\"debian7dev.dyalog.bramley\",\"port\":\"4502\"},{\"type\":\"connect\",\"ssh_auth_type\":\"pass\",\"ssh_tnl_auth_type\":\"pass\",\"name\":\"dfsaix\",\"host\":\"10.0.61.100\",\"port\":\"9003\"},{\"ssh_auth_type\":\"pass\",\"ssh_tnl_auth_type\":\"pass\",\"name\":\"mac0\",\"host\":\"mac0\"},{\"ssh_auth_type\":\"pass\",\"ssh_tnl_auth_type\":\"pass\",\"name\":\"local\",\"host\":\"127.0.0.1\",\"port\":\"9999\",\"type\":\"start\",\"exe\":\"C:\\Program Files\\Dyalog\\Dyalog APL-64 16.0 Unicode\\dyalog.exe\"},{\"ssh_auth_type\":\"pass\",\"ssh_tnl_auth_type\":\"pass\",\"name\":\"p7-61qa\",\"host\":\"p7-61qa\",\"port\":\"4503\"}]", "indent":"0", "kbdLocale":"en_GB", "lbarOrder":"← +-×÷*⍟⌹○!? |⌈⌊⊥⊤⊣⊢ =≠≤<>≥≡≢ ∨∧⍲⍱ ↑↓⊂⊃⊆⌷⍋⍒ ⍳⍸∊⍷∪∩~ /\⌿⍀ ,⍪⍴⌽⊖⍉ ¨⍨⍣.∘⍤@ ⍞⎕⍠⌸⌺⌶⍎⍕ ⋄⍝→⍵⍺∇& ¯⍬", "lineNums":"0", "pfkeys":"[\"\",\"\",\"{⍺ ⍵} \",\"FOO \",\"\",\"\",\"\",\"\",\"\",\"\",\"\",\"\",\"\"]", "selectedExe":"C:\Program Files\Dyalog\Dyalog APL-64 16.0 Unicode\dyalog.exe", "title":"{WSID} {PID}", "wse":"1", "zoom":"-2" }

Interpreter: Version: 16.0.30448 Platform: Windows-64 Edition: Unicode/64 Date: Jul 21 2017 at 20:18:55

[flouc001]

@dyaandys please could you test the branch I have created and confirm the issue is fixed. Then I can merge into master and ride4. Thank you.

[dyaandys]

Looks fine to me.