Problem with WiFi Kit 32 & I2C

In my project I am using an I2C compatible SI1145 light sensor connected to pin 21 ( SDA ) and pin 22 ( SCL ) of the WiFi Kit 32 board. The sensor functions normally, and correct data can be read from it, and displayed using the Arduino serial monitor at 9600Bd.
But when I also use the in-built OLED, there is now NO data and NO clock on pins 21 and 22 ( checked with a logic analyser ). So there is no communication with the sensor, and NO data can be read, although the OLED display appears to be functioning correctly displaying just the text, but the “sensor value” is nonsense, ( also on serial monitor if 115200Bd ).
It is my understanding that the OLED display and sensor are on separate I2C busses, because the ESP32 has two I2C busses. So what is going on ?
My setup is Arduino IDE 1.8.13, heltec.h library included in my code, OLED I2C0 0x3C, sensor I2C1 0x60.
In summary, the OLED and sensor when used individually and separately function normally. But when both are connected ( separate I2C busses ) only the OLED functions correctly.
Does anyone have the solution ?

If you want to use two sets of I2C, you need to initialize the two sets of I2C separately, such as Wire.begin(), Wire1.begin(). Or you can connect two I2C devices to a set of I2C interfaces.

Thanks, and I have used the commands you proposed in my sketch, but this alone did not result in a solution to the problem.
I have found that if I just comment out the following line of code:-
Heltec.begin(true, false, true);
my sensor immediately functions correctly and valid data can be read on the serial monitor though not on the OLED of course. ( Heltec.h library is still included as are other heltec display commands ).
Does this suggest that there is a conflict between the heltec.h library and the sensor library ? Should the library be edited in some way ? Can another library be used to drive the OLED ? For example a SSD1306 compatible library, possibly one from Adafruit ?
Could the sensor be connected to the same I2C0 bus as the OLED ?
Has anyone successfully used a second I2C device as well as the built-in OLED in the same sketch/project on the WiFi Kit 32 ( HTIT-WB32 ) board.

If you use Wire1.begin(), you need to replace all Wire.*** of the second set of I2C with Wire1.***, and you can set the SDA, SCL pins and frequency in Wire1.begin(). For example

The easiest way is to use the same set of I2C pins for the OLED and the sensor

It was always on my list of things to try and as I have exhausted all other possibilities without finding a solution, as a last resort I have now connected the sensor to the same bus I2C0 ( Wire.begin(4, 15, 100000) SDA=4, SCL=15 ) as the built-in OLED display. Now both devices are functioning together correctly. From the start of my project, I had hoped to avoid doing this by using separate buses as there are two, namely I2C0 & I2C1; but it seems that in my project this is not going to be possible. I have no explanation why this should be necessary !