It shows the value of variables.
It only shows when the execution is paused at a breakpoint. For example, here I placed a breakpoint at line 57 of the File > Examples > 02.Digital > BlinkWithoutDelay sketch:
The Arduino IDE developers are tracking something like this here:
opened 06:31AM - 23 Aug 23 UTC
type: imperfection
topic: theme
topic: accessibility
### Describe the problem
The current line in the Arduino IDE editor is indica… ted by a difference in the background color (AKA "highlight") of that line.
When using the "**Dark**" theme, the contrast between the color of the highlight and the background color of the rest of the editor is very low.
🐛 Users may have difficulty distinguishing the background, or not be able to see it at all (especially users with visual impairments).
### To reproduce
1. Select **File > Preferences...** (or **Arduino IDE > Settings...** for macOS users) from the Arduino IDE menus.
The "**Preferences**" dialog will open.
1. Select "**Dark**" from the "**Theme**" menu in the "**Preferences**" dialog.
1. Click the "**OK**" button.
🐛 The highlight at the current line in the editor has poor contrast against the editor background:
(the highlight is on line 2 in the screenshot)
### Expected behavior
The color of the current line highlight has sufficient contrast.
### Arduino IDE version
5fd02b9
### Operating system
Windows
### Operating system version
11
### Additional context
The demonstration above uses the highlight as an indication of editing position for the sake of simplicity. However, this is not a very compelling demonstration of the fault because the cursor also usually provides an indication of the current editing position, so the user may not be significantly impacted by the loss of an additional indicator of position.
A more impactful manifestation of the defect is when using the debugger. In this case, the current line highlight indicates the execution position when stepping. In this case, the cursor will not serve as an additional indicator so the highlight is the sole indicator of this crucial information. The user reports were in the context of using the debugger.
---
The highlight has good contrast when using the other officially supported IDE themes.
---
You must have the `editor.renderLineHighlight` [advanced setting](https://github.com/arduino/arduino-ide/blob/main/docs/advanced-usage.md#advanced-settings) set to "line" (the default) or "all" in order to reproduce the demonstration.
---
Originally reported by @KurtE at https://forum.arduino.cc/t/adding-debug-support-to-a-non-arm-eabi-board-type/1138076/9
#### Additional Reports
- https://forum.arduino.cc/t/mkr-zero-atmel-ice-win11-ide-2-1-1-fault/1158711/3
- https://forum.arduino.cc/t/debugging-on-the-new-nano-esp32/1153079/43
<a name="workaround"></a>
#### Workaround
1. Select **File > Preferences...** (or **Arduino IDE > Settings...** for macOS users) from the Arduino IDE menus.
The "**Preferences**" dialog will open.
1. Select anything other than "**Dark**" from the "**Theme**" menu in the "**Preferences**" dialog.
1. Click the **<kbd>OK</kbd>** button.
### Issue checklist
- [X] I searched for previous reports in [the issue tracker](https://github.com/arduino/arduino-ide/issues?q=)
- [X] I verified the problem still occurs when using the latest [nightly build](https://www.arduino.cc/en/software#nightly-builds)
- [X] My report contains all necessary details
However, I'm wondering whether you are referring to the same problem. The reason is that I find the contrast of the current line highlight is reasonably good with the themes other than "Dark".
Here I can see the execution point is at line 35 by the gray background color of that line when using the "Light" theme:
It is somewhat subtle, but I personally find it to be sufficient (I understand that it might not be for others, but we provide the "High Contrast" themes to accommodate that).
And here I can see it is at line 35 by the brown outline and line number coloration when using the "Dark High Contrast" theme:
Did I misunderstand what you meant?
